IIRC with 2008 R2, they didn't limit functionality if you didn't activate, they just took away the background and popped up a dialog when the system started. Activation was really only necessary to make sure you were licensed correctly (which isn't really relevent to TechNet/MSDN subscribers who could install as many copies as they want for evaluation/development purposes IIRC).

If they took the same lenient approach to activation (which probably isn't the case because it's a consumer OS), I could almost understand not giving license keys to technet subscribers, as their software is for planning/evaluation purposes only.