i was wondering... can we do a XBLA games sharing like PSN sharing?

i think should be possible, as I got 2 accounts on my xbox, 1 SG and 1 US

downloaded the trial Bionic Commando:Rearmed using my US account while playing games
then activate the BC:Rearmed using my SG account which still got points left
then i finished the full games on my US account

another example is my SG account was from another console, purchased castle crasher & lumines b4, now I transfer the account to my current new console, and I still can play the Castle Crasher as full version with my US account, but not lumines

wonder if it's possible for other games too, and is there download or activate limits?

it will be great if we can do XBLA game sharing, we can save a lot from there

i won't call it piracy, it's more of a grey area or loophole exploit
how many of us gotten the free games from the MW2 trial version bugs?

have a look at garage sales, there's multiple threads on PSN sharing, if it's really piracy, why aren't the mods taking any action?
maybe bcos we are still buying "orginals", hence they close one eye?