[ms office - 2016] Blocking specific users from attaching attachments

[Garacesh]

I know I can block certain users from sending emails with attachments via a mail flow rule of reject if attachment larger than 0.00KB, and I've done that, but these kids are using their email as a way to bring in pirated music and video game emulators from home (we disallow memory sticks). Rejecting the email means the email and attachment still end up in their Sent Items box and the attachment can be re-downloaded whilst they're in school.

 

Is there a way to stop specific users from attaching items in the first place?

 

* And yes, I know they could just upload the file to OneDrive, we'll cross that bridge when we come to it.