Yes, if you don't place them you keep them.
Early on you can raid pretty decent with balloons on people that don't have air defense. Just make like 15 balloons and wreck shop.
Right now (level 40) I like to make 120-150 level 4 archers with a few giants, goblins, and wall breakers, and target people with overfilled mines and elixer pumps, rather than wiping out whole bases. I noticed around 1250 ther's a LOT of level 70+ lurkers that appear to feast on the guys getting to that level of trophies for the gem bonus. Much safer around 1k trophies.
This post was edited on 2/14 at 2:39 pm