They also have a "don't misuse our services" clause and I'm sure this would count as misuse if found.
How come Google can figure out who and where the interested end-user is when emails are actually send by web apps and clicking is done upon email retrieval (I bet some cron with POP3). Moreover emails from "bad" countries are rather filtered out as spam/scam.
Apart of this thread publicly inviting people it may be also hard to distingush the accout from any busy one. But I guess G may have some pattern matching and rate limits for such sinks.
.. in your country. Saying something is illegal without mentioning jurisdiction is meaningless.
> not allowed by ToS
The service being signed up to, perhaps. But it isn't clear to me that it's banned by gmail's tos especially since he's using the service APIs normally.