I haven't worded myself well here but I mean I would feel more comfortable giving a card for dissent and the player getting 10 mins than I would if the player was on a yellow already and looking at a red for it. You can't tell me a referee hasn't put up with dissent rather than give that second yellow and send the player off. Having a player get instant repercussion for the dissent (10 mins in the bin) compared to a 1st yellow for dissent and no real repercussion (unless they end up with that red) would have a bigger impact on cutting it out also.
If a referee is putting up with dissent rather than dealing with it, then he shouldn't be there as far as I'm concerned.
Guess I should stop refereeing then.
Edit to say: If I refereed to the letter of the law, I would be handing out many more cards. But to be honest I do try and manage players first instead of giving cards, if I do get bad dissent or really loud/public dissent then I'm going to card the player.