Uh...it sounds like a crappy existence if you are able to be arrested anywhere, anytime. Even more so when you attract attention, as most of the time people only leave adventurers alone because they're doing a job for them, or they just aren't worth paying attention to.
The way this would go, the commoner would attract more negative attention. And the glacial rate of adventurer changes means that I wouldn't hold my breath. There have been a bunch of other suggestions about adventurers. But you know, you can really play your adventurer more creatively than you might think at first.
He can be an archaeologist searching for the lost unique items of the past like Indiana Jones, Medieval style with a Medieval style fedora (Which didn't exist but go ahead and roleplay that you are wearing a fedora. Some anachronisms that don't detract too much are fine. Besides, who said you couldn't be avant garde in BM?)
He can be a researcher of magic, traveling the world to seek the legendary wizards of old to gain their secrets written in their scrolls and one day become a magician himself. Not happening, but you could theoretically accumulate a bunch of scrolls and...do nothing with them because of the glacial rate at which scrolls become active.
