Unfortunately not.
Also no.
Thanks for all the additional details about the workflow, that's very helpful.
I think this is big enough and has enough potential for interfering with other planned and requested features that it'll need to be discussed at the TSC level. For example, I think another option would be to add a login/logout concept to Collect. This has been discussed in the context of tracking who has made changes when a device can be used by multiple people. There we're talking about some kind of authentication being involved but there could be an option just to request a user identifier as login and that's it.
What I would do in the mean time is start every survey with a question that says something like "Is your name <output ref="/data/username" />? If not, please exit the form, tap on the three dots at the top right, tap User and device identity, tap Form metadata and enter your username.". Note that I used Build syntax for the username field because you mentioned Build. In XLSForm one would use ${username}. I know it's not ideal but it should dramatically lower the risk of data coming in with the wrong name.