2) I can assure you there's policies at Microsoft that include performing work abroad and accessing any company resources from abroad. Obviously nobody will be approved to access any company resources from Iran, especially not source code.

3) I can say there is policies at MS this with a very high degree of confidence because I personally have done work with Microsoft involving code and data that is export restricted.

4) Companies should have policies in place in order to avoid situations like this. Taking your company laptop to, say, Germany probably isn't a big deal for most companies, but any "exporting" company assets should at least be pre-approved/documented.