This topic was discussed in an earlier thread. It sounds like the official policy is that you get the points for up to three rooms, provided you pay for them, but you should only get the nights for one room per stay, regardless of how many rooms you have booked. As noted in the thread, sometimes the extra nights are awarded, sometimes not.

As far as letting someone else use your MR number when you're not even traveling? It might be working for you, but it is clearly against the rules.