The point of the National Bike Registry, and similar schemes, isn't so much to prevent theft as it is to make it (sometimes) possible to recover a bike after it's been stolen.
Police departments do recover a lot of bikes; but, since it's usually impossible to trace ownership, most of them end up in police auctions.
The bike registries help to solve this problem, so that if your bike winds up in the hands of the police, there's at least a fair chance they'll be able to get it back to you.
If the tag is still on the bike, the cops (or a bike shop) won't have to look in five or six different databases.
They'll know which one to check.
But I agree it would be much better to have a single national (or better yet, worldwide) database.
I have a nice bike, and I know that there's no single way to prevent losing it to the creeps who go around stealing bikes.
But the more I do, the better my chances are.
bicycles.stackexchange.com/users/13277/Doug Rees
After reading this today, I called the three local law enforcement groups; Santa Cruz County Sheriff, Capitola City Police, and Santa Cruz City Police.
NONE of them use ANY of these online databases.
They all use a stolen bike database that is exclusive to law enforcement.
In California if the value of the bike is $900 or less it gets listed in a California only database.
If the value is over $900, it gets listed in a national database.
bicycles.stackexchange.com/users/24021/Dave
Bike Registration is a solved problem.
It's what Bike Index has done.
It's the largest independent registry in the world
It's free to register (it's not for profit)
It provides automated registration for bike shops Police use and search it
It does lots of other things and is open source
Bike Index recovers stolen bikes (> 2600 to date), because it works.
Additionally : Bikes have serial numbers, adding additional registration points (such as stickers) is counterproductive, since it adds one more thing to track (and another point of failure).
Disclaimer:
I'm a co-founder of Bike Index.
I built it because I was frustrated by existing registries and that they took advantage of bicyclist without delivering.
Reasons National Bike Registry is a scam: it costs money to register registrations expire (and aren't transferable) limited and inaccessible search for stolen bikes
No support, it's impossible to reach them no maintenance or updates Paying National Bike Registry for a registration is absurd, it doesn't do anything.
Don't give them your money.
bicycles.stackexchange.com/users/23057/sethherr
Its hard to say for a few reasons, but I'd be inclined to tend towards its not very effective: 1)
People have to be aware of it.
2)
It doesn't physically provide any security.
3)
The people who use this are likely to use it on nicer bikes so it could act as an attracting mark.
As far as I can tell, for the most part, the stickers could easily be removed or the bikes could be stripped for parts or more likely just used as is in a city (where delivery boys or whatever need cheap bikes frequently and don't really care where they're from, or whatever) - the bike would have to go through a bike shop which saw the sticker, and on top of that, did query the number in order to make use of it.
Or, recovering an impounded bike.
bicycles.stackexchange.com/users/8219/Batman
Having lots of bikes registered would make the registry more effectively.
If bike shops automatically registered every bike sold and governments that license bike automatically registered every bike, the system would be more more effective.
these processes could be computerized so that the shops and government needed very little additional effort.
bicycles.stackexchange.com/users/22953/Ken Shelor
Perhaps we need a meta-index, one that searches all the bike indexers in all the countries, then reports on matches based on serial number / brand / engravings etc.
Something like a email RBL blacklist DNS searcher, like https://mxtoolbox.com/problem/blacklist/
Personally I'd expect the sticker to be one of those permanent ones, or forgo that and use engraving on the steel/alloy frame.
Downside is, police don't have a lot of time for low value recoveries like this, so there's no incentive to use these databases.
bicycles.stackexchange.com/users/19705/Criggie
The  National Bike Registry  is an nationwide registry of bikes with identifying information (serial numbers, make/model, owner information) in the US that is intended to help identify stolen or impounded bikes. There are of course other bike registries such as the recent  Bike Index , many municipal registries, and the  International Bike Registry .  Are these registries effective, both at reducing bike theft (i.e. if you put a sticker on your bike thieves are less likely to steal it) or in tracking down stolen bikes?
Does the National Bike Registry work?
bicycles.stackexchange.com
<theft>
bicycles.stackexchange.com/questions/23229
bicycles.stackexchange.com/users/11331/Jason
S0: The point of the National Bike Registry, and similar schemes, isn't so much to prevent theft as it is to make it (sometimes) possible to recover a bike after it's been stolen.  If bikes are registered then, if they are found by the police, the owner can be located. However, cyclists views on how effective it is differ. Some believe it works but the majority see it as in effective. Unfortunately, not all bikes are registered, the police have little interest in low value bike theft and many people are not aware of it so it is pretty ineffective. The point of bike registries is for recovery rather than prevention, but since bikes are usually lower value and there are several databases, there is limited success matching stolen bikes that have been found to their original owners. Some databases are expensive with little support, and many bikes end up in police auctions. A tag will help police to find the bike on the right registry, but it provides no physical security against theft in the first place. Tagged bikes can also be used for parts, stripped of tags or used in the knowledge that they are unlikely to be traced.
The point of bike registries is for recovery rather than prevention, but since bikes are usually lower value and there are several databases, there is limited success matching stolen bikes that have been found to their original owners. Some databases are expensive with little support, and many bikes end up in police auctions. A tag will help police to find the bike on the right registry, but it provides no physical security against theft in the first place. Tagged bikes can also be used for parts, stripped of tags or used in the knowledge that they are unlikely to be traced.