Would this be pirating?

I'm taking a trip to a friends home for the weekend.  I was thinking of bringing DG, and installing it on his computer, so he can take a look at the game (he purchased Sins+Entrenchment, and has Impulse of course).  But would that be pirating?  If/when he buys a copy, will that mess up something if he already has it installed?

I hate pirates, so I don't want to be a hypocrite or get my friend in hot water.