Discipline tips I wish I had never followed

Years ago, in some parenting magazine, I read that with good behavior, my little darlings should be able to earn back anything that's gone into time out. If a beloved toy went in time out but they cleaned their room, they could get their toy back early, for example.  It made sense--we want them to learn from their mistakes, so why not teach them that better choices gets rewarded?  We implemented it without fail and had some success.  The girls were willing to do whatever it took to reduce their sentences and we got our house clean. Seemed like a winning combo, right?  Wrong.  I am now realizing, now that my older girls are teens, that what they figured out was that the consequences were fairly meaningless.  If they could always get them reduced, why bother following them in the first place?  A friend of mine gently suggested that doing extra chores doesn't address the issue (although having a clean bathroom is really, really nice, dagnabit). Instead they should complete the consequence without grumbling and NOT do whatever they did to get in trouble in the first place. If they were lying, they need to be superbly diligent in telling the truth. If they were out late, they commit to being home early. It's knowing that the expectations AND the consequences are clear is what can deter stupid behavior.  Huh. I knew we were in trouble when I told my kindergartner that she could have a treat if she got a green card at school (green--good behavior, yellow--warning, red--big trouble).  She ended up with a yellow card that day but still wanted the cookie if she did chores. Hoo boy.  Hopefully I'll figure it out a little sooner with her.