my ds1 (now 2) always stood right in front of the tv and would touch it/bang it/etc. 9 didn't mind him touching it really but it was a prob when we went to anyone elses house who did mind.
we've (mostly) solved it by accident really.
we bought him a small chair - for camping, (haha only been once) - and as our sofas were too high for him to climb up when he was smaller we brought the camping chair into the living room. it's now his tv watching chair - drinks holder and all (for milk i hasten to add!!)
if he doesn't sit nicely in his chair the tv is not on/we pause the programme.
it's working so far...