I've only dealt with their escalation engineers on sql server within a production scope, but i can say that in every incident, they have been top notch, world-class professionals (cannot say the same with other software vendors). I agree it's a waste to have the tickets and not use them. You end up learning other things during the investigation.
If in doubt, just ask... I'm sure the first tier folks would verify if your issue was within scope.
to answer the question about reproducing in the non-prod environment... i think this is a gray area. some things are impossible to reproduce especially if there is a load component or "you simply don't know" component to the issue.