Black Shadow, the fines are part of taxation, so if you don't qualify for taxes (for example, if you don't have a job that pays qualifying income), then you're off the hook, I'd wager. They aren't going around asking for papers, because that's dumb and a waste of police time, money, and resources. They'll probably just have another question on your tax paperwork asking for your insurance provider and member number, and a checkbox for those who wish to forgo insurance and pay the (relatively small) fee.

If the homeless were going to be arrested for things like this, which are part and parcel with being homeless, it would have been happening for decades. The homeless don't pay taxes, because they don't generally have income as far as the government is concerned. If they do have any income, the government tends to turn a blind eye to it because, seriously, taxing a guy who made a couple hundred dollars in a year is a waste of, again, time, money, and resources.

In essence, there's nothing to worry about there, because what you're suggesting is completely infeasible and impossible to enforce.