I never got caught for detention, but sometimes yes. The best thing to do is put the tama on a thingy round ur neck and if ur desk is higher than the tama, u can check it when ur teacher isn't looking. Once this year, my friend accidently reseted my tama and it beeped alot.. I started to fix it, but no-one noticed! lol! But my teacher saw me playing with it afterwards and she still let me have it in class, but never took it away.
Once when I was at tutor, I had the sound on and I was trying to turn the sound off and the class was quite, I didn't get to but it beeped alot (when I pressed the C button on my V.5). But the funny thing was that my teacher didn't notice it, but instead a kid did and he didn't tell on me! And he noticed it again when it was 10:00am for trainning! LOL!
And once when I was in year 3, my teacher let my friends and i play with them in spare time! She didn't care! LOl!