My issue isn't with the 'randomness' of it, I was more annoyed at the situation the substitutions occurred. There is no reason to make a sub with 20 seconds left in a blow-out game, other than injury or foul out. In the other situation i explained, basketball rules (at least in England) are that if you are subbing in for someone shooting a free throw, you don't sub in for another player, you have to wait until the next opportunity to sub in.
Having subs mid-game (3rd quarter for example) could happen for many other realistic reasons (low stamina, needs a rest etc) which i could understand.