Being Careful

As I mentioned a few weeks ago, Tristan broke his arm (elbow in two places, plus wrist) at football practice a few days before Halloween. 
Here he is a few days after getting his cast on (this also happened to be Crazy Hair Day at school):

When he got the cast on, the doctor gave us strict instructions to have him be really careful - he did not want him doing any further damage to the bones, or falling and hurting his other arm. 
He told us no running, no climbing, no playing around, no recess, no P.E., etc.  I could tell as soon as he said it that this was going to be the hardest part of having a cast on for my active 7-year old boy.
After Tristan's first day back at school with the cast, I talked to him about how the "careful" plan was going:
Me:  Tristan, have you been being careful?                                                                        
Tristan: Yes.                                                                                                                       
Me:  What did you do at recess? Did you just read a book inside?                                
Tristan:  No.  I played outside but I was really careful and just dribbled a ball with my right hand.                                                                                                                            
Me:  Oh. I think it might be better if you just stayed inside.                                           
Tristan:  Oh, man! Please?                                                                                               
Me:  Well, okay - I'll let you be the judge of what you think is a good idea and what isn't. Just be careful.                                                                                                                
Tristan:  Oh, for sure.

A few days later. . ..

Me:  So, what did you do at recess today?
Tristan:  Played soccer.
Me:  Tristan!
Tristan:  Mom, I was totally careful. I didn't even run. I just did this. .. (demonstration of really fast walking). Oliver: what even is soccer?
Me: it's a game where you try to kick the ball into the goal but you can't use your hands.
Tristan: Except the goalie can use their hands.
Me: How did you know that? (his soccer experience is limited) Tristan: Well, I played goalie today.
Me: Tristan!

A few days later...

Me (suspiciously): How did you get this hole in your pants and big huge sore on your knee?
Tristan (guiltily): I fell.
Me: Tristan! What were you doing?
Tristan: Playing tag.
Me: Tristan!! What were you thinking?
Tristan: Mom, I promise I wasn't even running - I was just "juking"!
Me: Sigh.

Now he has the cast off, and is supposed to wear a sling for 3-4 more weeks.  That lasted about one day.

I don't even bother asking anymore - I figure I'm better off not knowing.