I'm thinking there could be situations where a man who didn't want to be a dad could then get the pills through someone he knows and slip them to the pregnant woman.
Not really very likely in my view. He'd have to find a pregnant woman in her first trimester who was willing to pretend she wanted a termination and then get her to go through the whole appointment procedure.
I briefly considered the possibility of women getting these pills to sell on, but dismissed it as equally unlikely.
I can't think of a logical reason why women shouldn't be allowed to take these pills at home. If there was a risk to health then women would have to stay in hospital for the duration, the fact they're allowed to leave at all suggests the risk is minimal.