I agree with the posts here and have no worry about the Montreal scene, which is fantastic. But we (clients) are also very spoiled in Montreal because screening is about as painless as any place in North America. Agencies, of course, do not screen; and indies are very generous about seeing merbites with a history of sanity out here and with a reference from another provider. But it can be a very different scene in some of the big US cities; and, while I haven't used the verification services like preferred411 in a while, I have used them in the past--and they took not only my personal information (which they did verify) but my workplace/office information. So, especially for those of us who are married and have community-sensitive jobs, that's pretty hefty leverage they have. And while I have never felt threatened by an SP, I would certainly think twice about writing a (fair) critical review of someone who can obliterate my life in a second. For that matter, we've all seen posters out here who have written "meh" reviews or worse of popular SPs, only to get slammed by the chorus of fans. That doesn't happen often, and sometimes it's hard to tell what is "fair," but it does happen. My guess is that, for good reasons and bad, many of us don't want to write negative things--if only because ymmv, but also because we're polite and don't want to hurt feelings or hurt a girl's business. There's a lot at stake in a bad review--for both provider and client.
Anyway, thank god for Montreal and the great scene it offers.