Interesting, in Quebec I've never heard the conjugations to the left!

When we need to strategically indicate this kind of thing, we just curse excessively. Often they are strung together into a profane litany that continues on for some time! I always thought it was quite artful.

Like Saigonauticon, I've never heard any of these!

In my neck of the woods you'll find people adding a first person plural ending to third person plural verbs (ex: "elles mangeons" instead of "elles mangent") which is common enough to not bother me or strike me as a sign of stupidity, and at least differenciates between the singular and plural forms of a verb.

One thing I didn't mention in my original comment that does bother me is something kinda similar some people do with the verb "être", like a teacher I had in high school. Instead of "ils étaient", she'd say "ils sontaient", simply adding the typical imparfait conjugation ending to the present "ils sont".

Les cours avec elle sontaient un peu tristes, et malheureusement assez représentatifs de la qualité de mon enseignement.