Windows Server 2008R2 Virtual Lab Activation strategies

I have a ESXi server that I use for testing, however, I am often needing to create additional Windows Server virtual machines.

Typically, if I do not need a VM for more than 30 days, I simply do not activate.

However, I have been doing a lot of HA/DRS testing recently and I have had a few servers up for more than this time.

I have a MSDN account with Microsoft and have already received extra keys for Windows Server 2008 R2. I am doing nothing illegal and I am sure if I asked, they would issue more – but, I do not want to tempt fate!

I have got 3 different "activated" windows snapshots I can get to at any time.

If I try to clone these machines, I get the usual "did you copy or move them VM" message.

If I choose copy, as far as I can see, it changes the BIOS ID and NIC MACs which is enough to disable activation.

If I choose move, it keeps the activation fine (obviously, I know to change the NIC MAC – I believe I can leave the BIOS ID without problems).

However, either of these options keeps the same SID code for the computer and user accounts.

After the activation period has expired, as far as I can see, all that happens is optional updates do not work – it seems that the normal updates work fine. Based on this, as you can easily get in to Windows when not activated without any sort of workaround, I was wondering if it is ok just to leave a machine un activated? (However, I obviously would prefer if it was activated!)

Alternatively, how dangerous is it run multiple machines on a non domain environment with the same SID?

I am just interested to know if anyone can recommend a strategy for me? I have only found one solution that deals with bypassing activation – I am not interested in doing anything remotely dodgy… at a stretch, I am happy to rearm (I have never needed to keep a server past 100 days), but, I would rather have a proper strategy in place.