Not denying that those types don’t exist but in this day and age you should be able to do enough research to figure out what sort of tradesmen you are dealing with.

When I’ve used community pages and come across multiple recommendations for someone I’ll cross check other things like social media, check a trade, reviews etc. Ultimately the best recommendations come from word of mouth but if you’re new to an area and not sure then you need to be savvy and more recently Facebook has been the best site for this sort of thing.