Slow over rates are endemic all the way from test level to the lowest of the amateur leagues. That rule sounds entirely sensible to me.
It is definitely the way forward, however the only problem is it is only enforceable in our top 2 divisions (we are in div 1) because there are no league umpires below that.
When you don't have any umpires major arguements can ensue because it takes very strict governence during the game, even in div 1 and 2.
Teams are always asking for more time for lost balls etc... then it's down to the umpire to decide how much time to add on. So it doesn't work when you don't have umpires unfortunately.
We won a game earlier in the season from penalty runs. We were chasing and the oppo were miles behind the rate and it came down to the last wicket. In theory we would of needed 24 but they we penalised 3 overs so 18 runs, so we only needed 6 ! Got them easy. Of course oppo kicked off massively, but it was a league umpire who told them so nothing they could do.
Can you imagine that happening in Div 7 with a player umpireing! There would be riots.