The OP blames "various idiot web 'designers'" for problems, but in my 30 years of being a web designer I have yet to meet one designer that wants to cause these problems. It's usually people responsible for generating revenue.
In my practice, I'll try a Jedi mind trick, e.g. "Trying to [state larger goal] makes a lot of sense. An even more effective way to do that is to [state alternate, non-toxic technique]."