Just because it’s an edge case doesn’t mean 30% of your userbase won’t encounter it!

I work at a company whose entire business model is providing QA to other companies. I work directly with some very large, public companies, and some smaller ones. Almost all of them have some form of dedicated in-house QA, which we supplement.

Why not just make a secondary ‘real’ email account that you use exclusively for signing up for things? Gets around those problems and gives you a way to retrieve recovery emails if you ever actually need to.