Russian-speaking users say this action is not limited. They tried and got licences from that reseller though they typed in e-mail addresses from RU zone (like Mail.ru and others).
I rather doubt they have any sort of filtering as presumably the process is automated, you give your details and an email is sent.
The actual email address isn't a very good means of deciding where the user is as it is easy to get email addresses, so they would have to capture the IP address you used when completing the form (easy) and ensure it is geographically correct for the offer. That means work and they probably don't want to turn away possible future customers who might purchase at the end of the free period.