Marty, I've never had anyone refuse to sign a model release. It's not a big deal to them unless you make it feel like a big deal.
I do get people's consent, however I don't make compensation in most cases. People are usually flattered that they or their children are so attractive that you want to publish pictures of them. I've never had anyone get creeped out about it, especially because I always explain that no personal details about them will be disclosed outside of first names and possibly the general geographical area, i.e. Venice, Italy. People are generally very reasonable about these things.
As far as street photography, in the US the key is that there is no reasonable expectation of privacy when in public, so street shots of people are usually untouchable. If you photographed them sleeping on the sidewalk, it's fair game; if you photographed them sleeping in a private hedged-in backyard hammock by climbing over the hedge and stalking your prey, it's probably not fair game. I believe the law is similar in Canada, but don't take my word for it.