You are right when it is in the middle of the game but imagine at the fag end of a game with maybe a couple of runs needed and the last pair going for a desparate run, the poor fielder may be faced with an absolutely impossible choice. He will be cursed if he doesnt throw and cursed if he sends it for over throws.
Yeah but that's life, isn't it?
You take a risk and if it comes off, reap the benefits. If it doesn't, life sucks. It's all part of the game (which, contrary to popular belief, it still is). You win some, lose some.
Disallowing leg byes is another thing which can be considered. Just imagine, an in swinging yorker hits the batsman's boot just outside the line of the off stump (a sure clean bowled but for the boot) and the ball screams to the fence and maybe thats the end of the match.
Not too fair, is it?
Indeed it strictly isn't but, put in the situation myself as I've been before (bowling the last-over, not many to win, etc.), an in-swinging yorker isn't a high-percentage ball because of the risk of that happening. Similarly unfair is if I bowl a bouncer which a batsman gets a top-edge to and gets four winning the match. It's still a low-percentage tactic and put in the situation, I try to avoid doing stuff like that. If I give a ball like that a go, I do so with the full awareness that although I might force the issue and nab a wicket, it may well all go to crap too. Deciding on tactics, etc. is all part of the fun and that uncertainty is what gives those moments their magic. It's what gives cricket it's x-factor. If I, as a bowler, knew a batsman couldn't get runs if they didn't hit the ball with their bat, the uncertainty would be lost a bit and the game would be a bit easier for me. I dunno about you, but I don't want cricket to be easy.
Perfect example; Tied Test 1961. The ball that got Benaud (top-edge hook to a player who played it well) could so easily have flown away for four which would have cost the WI the game. But Wes Hall took the risk and got him. The fact it had risk was what made the moment great and Wes Hall's action all the gutsier. If he'd gone for four, Wes Hall would have been derided as stupid. As the great Nigel Tufnel said in 'This is Spinal Tap', "There's a fine line between clever and stupid."