The smaller run-around-balls are cheaply made and after a few weeks the lids don't hold right and you either need to tape the lid or put an elastic around them.
I took the lid off of my hamsters once and she didnt want to get out.. She just sat there until I put the lid back on and let her roll. She loved her ball.
Well Dizzy you and my hamsters do not share the same opinion. When hamsters don't like them then they chew the ball or just sit around, maybe sleep and eat a little. I have only had one hamster that didn't like her ball so much so I didn't force her. These three especially like their balls, I have to entice them out with treats when playtime's over.