My Dogs (4) all know how much they can get away with, and with who. If I open a door they wait for me to go through first, the rest of the family.... well lets say they have to be careful not to be trampled!
Also 2 of them are on diets and I have my family on strict instructions not to feed them, but they know if they bug someone else that isn't me..... one of them will relent and feed them!The whole "awww... poor dogs haven't you been fed?" or to me " gee your mean, you mustn't fed them enough! They're still hungry!"
Likewise, my sister's terrier X obeys me when noone is there to 'save' her. If my mum or sister is there, she knows all she has to do is run to them and look sad/cute!