via http://psp.dashhacks.com/2012/02/09/...league-its-own

In a discovery of the disappointing kind, PS Vita gamers with purchased PS1/PSP content online have found that the Vita and PSP are classified under the same activation count.

If you own any amount of PSP's and have game shared up to the limit (5 consoles, 2 for newer games) then anything you choose to download to the PS Vita will be denied due to the activation limit being reached.

I have covered the topic moreso on PS Vita-Hacks here, but as well as myself, many others I discussed this with thought it was safe to assume the PS Vita was in a league of its own in terms of activation counts.

Best you go and choose your activated PSP's wisely, and save a slot for your Vita. You will need it.