How come I can backup all paid apps but only install some of them?

[computerboyo]

Hey,

I backedup all my apps and I just realised that I can re-install them again, so technically I could of purchased an app and backed it up and then refunded it and then installed it from the SD card.

Some apps I have backedup but they won't install, is this down to the developers choosing to protect their apps or not.

 

[cigar3tte]

You also can't get updates doing that.

As for protected apps, I can't back them up at all.