just this week I’ve had multiple random matrix accounts start a chat with me to post an Imgur link with some Hitler bs. I assume they just chose random members of one or more fediverse related public matrix rooms to send that to. they probably just do this with random public rooms and the fediverse relation didn’t matter.

it doesn’t seem to be server specific because once prompted there is no way to use the account again, even if you decided to just not use a server that may have these settings set.

no, you’re also effectively locked out of any participation unless you provide an email address and phone number, which they won’t even tell you about in advance but use dark patterns and gaslighting that they noticed “suspicious activity” to step by step first ask you for an email and then once that is validated they prompt you for a phone number. the only thing they don’t do yet is ask for ID.