I think they were willing to train and work so far as that went. For the shot they couldn’t practice firing their pieces unless issued with powder and shot. It seems a very counter productive system until we remember that the social upheaval in England had produced large numbers of newly impoverished men. It was these men who were impressed for the army. Many of the Captains were only interested in profit. To them the soldiers were expendable they could always get more of them.
The soldiers also keenly felt the lure of desertion. If they could keep a little from their pay and then sell off their kit which was easy enough they only had to find an English ship. The Captain was empowered to issue passports and once paid would do so. Once back in England they could disembark as civilians and blend into the dockside crowd.