I suspect the real problem here is that identifying when ownership has changed is pretty much impossible unless you are the registrar. Assuming you could even fetch them (they probably are rate limited) the whois record could change without indicating an ownership change or even the DNS could change without indicating an ownership change. Also, even if there was no change in these records, the owner might have changed. The new owner, if an attacker, could put the same data into the whois record and use the same DNS records. The domain may never even "expire" officially with some registrars letting a new owner grab a domain before the official expiration drop.

I assume the previous owner probably has some mechanism for deleting the accounts that are currently on Google Apps. If that's so, then it seems reasonable that it's their responsibility to do so.