So, judging by the principal meeting, I suppose the movie takes place during the school year. Let’s debate; what excuse would Dash and Violet submit for missing school? Or was it over a weekend?
Being sick?
Death in the family?
Family vacation(which, technically it was)?
other family emergency…?
Good question.
I’m sure Helen could come up with a brilliant excuse. Besides doctor, death in family, vaction, and others. If not, just say “we traveled to an unmarked island, where we were caputred, rescued, and we fought a giant robot in the city all in two days!” 
Plus, considering that the final battle took place right in town, I’m sure that their teachers and principals were aware of the situation.
You think they would get suspicious. What is one of them walked into a room with the mask on. How does that even protect there indenty? Villian- “mmm, You look familiar but the mask that bearly covers your race ruins that, I never find out.” Superman was somehow able to do that WITHOUT a mask.
Well, Clark Kent wears glasses, so that’s his “mask”.
rock-itpop, I guess they would say it was a family vacation. But, I wonder what they would do if the faculty got nosey, like Pixarfan91 said.
I’m sure that the family can explain it for one day. But with a giant robot attacking the city, you would think that the city would declare it an emergency, sending kids home to be with their families.
That makes sense. Or it could have happened on a weekend, making any excuse unnecessary.
I think us as the audience are left to ask which of the days the Parr family left on. But it is a good point to make.
It’s just so fun to speculate on things like that, where they don’t tell us. Then we can personalize the story to an extent.
I guess it all depends. Maybe there was a long weekend or something lucky!
And why DON’T people see who they are, even with masks? I think it’s pretty easy to tell. Frozone is fine, but their masks are so puny
Well, it is a movie. 
And Superman got by with a pair of glasses, which is even smaller.
Good point though. The masks won’t nessecarilly conceal their identity, but it looks cool.
Let’s get back on topic tohugh.
I think the mask thing makes no sense on purpose. It feels like a tribute to the campiness of the super hero genre, like many other aspects of the movie. The masks also would probably be distracting if they covered more of the face.
I just noticed that this forum does have discussions on not only the masks, but the kidsat school as well.
Here you go.
[url]What Did You Notice In The Incredibles? - The Incredibles - Pixar Planet Forums
Locking up now.