Observations on Having a Mohawk:
Musicians, especially of the punk, indie, or rock variations, automatically pay attention to you. It's a bit like joining a secret club. Your opinion matters, you are acknowledged in a crowd, and you are introduced to their friends.
People want to stroke your hair. This is natural. This is not always a flirtatious behavior. Your best bet, if you desire a good laugh, is a request that the petitioner stroke your hair "sensuously". This rarely results in physical violence.
People, even those of conservative natures, compliment your haircut. Yes, even your parents, teachers, and local policemen. Reason: no one wants to be uncool. Insulting a mohawk is basically the most uncool thing you can ever do.
No matter how short or tall your mohawk is, you will duck to get through anything shorter than an 8 foot tall doorway.
Disclaimer: This list is based on changes I've observed while living in a large Southeastern American city, going to a small liberal arts university, and taking the train to school every day. Your mileage may vary.