I print labels and we require proof approval from customers. This means the files I end up using ultimately get opened by at least 3 people. Any number of these people can save the files so that edges are hidden, however, on my end, I always want edges shown so I can better see where they are in relation to the white cut box (FXCUT) that's against the white background. I also maintain our proof templates, which, similarly, ends up being opened by multiple people.

The idea I propose is that there be a global default setting for each iteration of illustrator on any given account that allows that specific user to have edges shown all the time, none of the time, or on a file by file basis.