If you are in two point correctly you are not going to throw your horse off balance by giving with your hands. If she doesn't start now when she is just starting out, it's going to be a lot harder down the line to unlearn the habit of not releasing over the jump. It doesn't matter how small the jump is, you have to release. Especially if the horse is making a big effort even if the fence is only 1ft. Heck, even if her mare was just making a large canter stride over the jump, she should still make that effort to give with her hands.
If her two point is solid, all she has to do is move her hands a little bit up the neck and grab some mane - the crest release. And leave the jumping effort of her horse to close her hip angle.
Have you tried setting up a ground pole two or three strides after the fence? It gives the horse something to think about so their first thought isn't bolting after the jump.
[COLOR=DarkRed]Well behaved women rarely make history!
Fpzipsdreammachine "Booty" 2006 AQHA mare