I have solved the Jurassic Park problem! (Ie how do you stop their inevitable revolt/escape)
Hay fever!! Grass didn't exist in the Jurassic. So just make sure they all have hay fever. They will be dependent on humans for their supply of antihistamines and will be easy to locate/avoid from their powerful sneezes when they escape.
You're welcome, evil theme park mogels! Honestly it's amazing you haven't thought of this before.