We've been doing this since Ava was 1 (she's now 3) and Travis was 3 weeks old (he's now almost 15 months old).
Both of my children, who are generally shy in public (who knew!), have taken to having temper tantrums (Travis) or blatantly disobeying and ignoring their teachers (insolent Ava). I wouldn't have believed it if I hadn't seen it for myself.
Travis throws himself flat on the floor and lays there wailing and occasionally licking the carpet. He also SCREAMS if someone takes his toy ... so much so that the children give it back to him in fear. The teachers are just as surprised at this behaviour as I am but I think I find it funnier.
The other day, while Miss R was taking Ava to the washroom (it's outside their classroom), 
Ava decided to run away from her to the end of the hallway and not listen or come back. Once Miss R finally caught up to her and convinced her to come to the washroom, Ava was really pissed off with her and wouldn't look her in the eyes the rest of the morning. While in the lavatory Ava demanded Miss R "close the door - I need privacy" in a not so nice way. Let's just say I was in and out of the room a few times that morning. After trying to unsuccessfully convince her to apologize to Miss R for not listening I gave up. Then, in the car on the way home, I hear from the back seat "I want to give Miss R a hug". Uh-huh, sure.
Ava decided to run away from her to the end of the hallway and not listen or come back. Once Miss R finally caught up to her and convinced her to come to the washroom, Ava was really pissed off with her and wouldn't look her in the eyes the rest of the morning. While in the lavatory Ava demanded Miss R "close the door - I need privacy" in a not so nice way. Let's just say I was in and out of the room a few times that morning. After trying to unsuccessfully convince her to apologize to Miss R for not listening I gave up. Then, in the car on the way home, I hear from the back seat "I want to give Miss R a hug". Uh-huh, sure.
Hopefully there will not be too many repeat occurrences of these behaviours. I secretly am thankful that they happen at school and not at home!