if I was to do something rite now I would jus use a hotspot or jack somebody's AP. I mean, they might be able to trace it quick but unless you go somewhere that has cameras it's pretty safe. but then again, we're all a little paranoid here. law enforcement agencies only solve haking cases if:

1. the hacker was very stupid
2. the hacker went on IRC an bragged about it
3. there is a lot of media attention about it
4. the hacker defaces a website and his hacking name is his real name (jonconley)