Android and desktop. I'm no UX designer, so I don't know what the ideal is, but when I'm using the software with a purpose, anything that gets in the way of that purpose is (at best) an annoyance. I'm probably wrong, but I think I'd prefer a passive notification to verify pin / donate / whatever that triggers after/as I leave Signal for something else -- a indicator I'm done with my purpose (albeit flawed; maybe I just need to copy info from FF or whatever.)