Lion across multiple machines.

No, that would be a breach of the EULA. Software can only be installed on Mac's that you own.

 

So you are gonna have to marry her to get lion.

 

Or move in with her?

 

Logout of the mac app store on your mac, and log back in with her account, click "buy now" and it will say "you have already purchased this, click ok to download" after your click buy.

After this, change the username and password back to yours.

Super simple.

 

buy also violating the EULA.

 

"buy"? You're an educated individual, aren't you?

Just because his girlfriend has her own mac app store account doesn't mean that they are violating the EULA by using her license to install on his macs as well. There is no way to determine if her mac is actually hers, or if his is actually his from the information given. She could be the administrator, and owner of all machines in question - so could he. If HE purchased lion on his girlfriends mac, that stands to reason that he is the system administrator and owner of the systems in question. This was never stated and can NOT be assumed, however.

Pay attention.

 

Sorry. auto correct made it buy. I clearly mean but.