And yes: it is an incredibly simple thing to avoid, and yet it is also a deceptively difficult thing to fix and cleanly walk away from later when the other party actively wants you to not exist as you are often now stuck in a really shitty position with respect to the hole you have already dug yourself into and the legal fees you are potentially going to lose just trying to defend yourself going forward. Hell: someone I don't like from the "extended" Cydia ecosystem (if nothing else: they are the kind of person who thinks they are above trademarks) once even just hinted on Twitter at building a product with the name "Snapchat" in it (which I obviously would never have sold as I was really careful about this sort of stuff) and their lawyers started coming after me with a cease and desist for something I wasn't even going to do, costing me thousands of dollars to deal with (as their lawyer knew to directly contact my lawyer, making it harder for me to avoid any costs).