In working with Canvas Support about a permissions issue (I was trying to remove the masquerading privileged from a sub-account admin), it was brought to my attention that, "The reason that this "Become" option is showing up for you when it should not be is due to a permissions override. Because you are an admin with those permissions, masquerading as a user who doesn't, it is defaulting to the highest permission available to the original user, which is why it showing for you. I created a backdoor entry for this user and logged in as them and was able to confirm that they do not have access to this."
In addition, I know that in the past Canvas Support has let me know that when I masquerade as people (students and/or faculty) I won't actually see the Canvas Inbox the way they see it. It will be different and could likely be missing messages and conversations. They recommended creating an alternate login for situations like this so I'll know for sure that what I'm seeing is really what they are seeing.
I checked the Masqurading guide - How do I masquerade as a user in an account? - and there's no mention of any of these potential issues (I posted asking to get something added), but I'm wondering if there's any other issues like these that Canvas Admin's have noticed with masquerading? Have any of you noticed any other strange quirks or things that don't come up correctly when using this feature?