I think the police have better things to do. Plus, the only way they would actually be able to figure out who you are is to seize Cannabis.com servers and go through logs, or subpoena Cannabis.com and ask for their logs. But that is extremely unlikely.

Also, the fact that you could be surfing the 'net through a proxy would make proving that you are actually you in court would be REALLY hard.

Also, be discrete. You know, don't be like "Yeah so I went down to Fred's Garden Supplies on Rt.15 in Hackensack" because that tells everyone that you live in Hackensack.