Honestly, it makes perfect sense to me - most of the spam I get through non-google instant messenger accounts is in the form of invite spam, and if they're seei

Honestly, it makes perfect sense to me - most of the spam I get through non-google instant messenger accounts is in the form of invite spam, and if they're seeing a massive spike of that then temporarily blocking them isn't entirely unreasonable. So long as it's temporary (and given you can request whitelisting in the meantime), I don't really see the problem.