DEPR: passing mixed offsets with utc=False into to_datetime
xref #50887

parsing datetimes with mixed time zones will raise a warning if `utc=False`. We advice users to use `utc=True` to silence this warning. 
@MarcoGorelli, could you please take a look at this pr? Just xrefing https://github.com/pandas-dev/pandas/issues/54194 as an example of a user wanting to maintain mixed timezones in a different operation thanks for the reference

this would still be possible, just not via `to_datetime`

still, I'm curious to ask what their use-case is nice

I'd have thought the warning would show up in at least some `read_csv` cases - is there no test case for `read_csv` where the input data has mixed offsets? If not, could we add a test for that please (either here or in a separate PR), so we can check that no warning is raised there (as users wouldn't be able to silence it)? > I'd have thought the warning would show up in at least some `read_csv` cases - is there no test case for `read_csv` where the input data has mixed offsets? If not, could we add a test for that please (either here or in a separate PR), so we can check that no warning is raised there (as users wouldn't be able to silence it)?

Thank you for the comment. Seems like there was no test for `read_csv`  with mixed offsets. I made a separate pr for this. Sure, thanks - I don't want to force this onto the project, I really want us all to be happy with what we're doing

Suggestion: we get this into 2.1, and then if there's complaints or issues we hadn't foreseen (or use cases for which the workaround suggested isn't enough), then we revert for 2.2 / 3.0? Getting it in for 2.1 would give more time to hear people's potential complaints. Happy to admit I've been wrong about this, and to revert course, if that happens Great work @natmokval 

I do like that this will not catch users by surprise with `object` dtype from `to_datetime`. Yeah let's see if we get feedback from users in 2.1 > Great work @natmokval
> 
> I do like that this will not catch users by surprise with `object` dtype from `to_datetime`. Yeah let's see if we get feedback from users in 2.1

thank you. I hope users will find this change reasonable. Thank you @MarcoGorelli for helping me with this PR. Why are we filtering warnings internally here? My understanding is that this will raise in the future, so we should give users the time to address things

cc @natmokval @MarcoGorelli  it's in a place where the user can't do anything about it, and where in the future it just won't get converted (the input will be preserved) as we'll no longer end up with an `object` Series of `Timestamp`s