Seriously?

Last week, we got an email at work warning us about some pesticides being sprayed. (Apparently we had some flying ants.) It went out several days in advance and we were advised to take any food out of our rooms before Friday at 4, which was when the building would be sprayed. So, you know...it's a big deal.

Or so I thought.

I guess I was wrong? I work the homework club after school (yes it IS the coolest club to join) and dash down to the cafeteria at the end of the day. Well, TODAY I got to my office at 4:30 to find not an open door, as I left it, but a closed locked door with tape across and a sign proclaiming KEEP OUT, ROOM SPRAYED. (Bonus: My office locks automatically.) (Double Bonus: My keys? Inside. Obviously.) Um...cool?
I ran around and found another teacher and borrowed her keys and warned her that if I didn't return in two minutes, she should check my office for my body. I darted in and looked like a spaz trying to get all my stuff together and figure out what work needed to come home. Then I sadly threw away the apple that was to be my snack, having visions of my colleagues finding me Snow White-style. Poisoned apple rolling away from my hand and all that.

So here is my question: why would one pesticide spray merit some warning, but the other one...not so much? (Also: will my box of Triscuits be safe to eat? Does anyone know about flying ant pesticide? No? Ok, thanks.)