I get that you may despise people who are sticklers about the rules, but consider what a typical IT staffer is going to be faced with. The typical "random device" user is going to say "Hey, Mr. IT guy, I want to hook my up to email. Any problems?"
Let's say I say, "Not really. Point it here and you're good." Let's even suppose further that I say "By the way, we don't support your . If it goes haywire, it's like this conversation never happened."
I'm still going to hear about it when something happens. It is still going to eat bandwidth in my day as I am rolling out a patch which also happens to sever the connection to s because they are incompatible with this patch. I am still going to have to reply to his email, even to say 'Nope.' Even to hit delete.
That's just personal inconvenience. On top of that and frankly of far more concern are the possible problems that may crop up because that device is connected to company resources. If it happens that some bizarre interaction between and a company server causes downtime or data loss, it's not the end user that's likely to get grilled, it's going to be the IT guy who let him connect his unapproved to the company network in the first place.