I suppose one thing we have to accept as referee's is we referee as much with our personality as we do with anything else. What works for one person might not work for another, and when using different techniques to manage certain situations we also have to be mindful that the way we may chose to do something will either work with a players personality too or won't. That's what we have to judge to the best of our ability at that moment in time.
Thats easy, whatever warning was coming just turns into the consequence! I have had a player once say something to that effect a couple of seasons ago: "I don't want to listen to what you have to say, just do whatever you want to do!"
Okay, have the caution. He took it without word and behaved for the rest of the game until a mass confrontation broke out and he got sent off for coming from nowhere and grabbing an opponent around the throat. No complaints, off he went.
Might sound odd, but I get on with him really well now.
A referee talking to a player is to try and avoid recourse to cards (did you really not see that?) if it is possible to manage a situation which is not a mandatory caution (those grey areas where you could caution, but can also manage it - let's not have that debate again today). Player would prefer not to have that talk, fine then they get the card instead. The referee is not dissenting against a player decision?
The situation where a shushing finger is used, A player is borderline dissent by arguing a decision/moaning. If you chose to use the finger to lips to silence him and manage the situation before it gets to the point where you have to do something about it and it works then why not? it being just another tool in the old tool box of ways of managing a situation. Would you use it all the time? No. You use your judgement as in any man management situation.
If I was just nattering to him about nothing and he did it, I would have no issue with it. Why would you?
Thats all I was trying to get at. If its general chit-chat and you would caution I would be worried. I'd not like a player to do this to me at all because I wouldn't do it to them, but I understand it may work in certain circumstances.