Because they WILL find any and every way possible to make noise.
If you take away the drum and drumsticks? They will beat on the basketball hoop with their plastic tools.
You take away those?
They'll resort to smashing their monster trucks into each other, each trying to "one up" the other to see who can make the loudest engine noise.
If you say its time to put the trucks away (because they came across the gawd-awful one that plays You Can't Touch This), they'll find some way to fight and squabble over every piece of crap toy that plays music that they've ever owned.
Or just a single Matchbox car they both must have.
And they will both pitch a fit when you take it away for fighting over it, ignoring the 8,362 other cars they have that are justthismuch different.
When your patience has worn thin, you'll probably decide that getting out of the house is a good idea.
But somehow, you may just figure that its a good idea to combine that thought with the beck and call of your to do list and brave the grocery store.
With two kids.
Who are already playing "Do You Want to Bet We Can Fight Over A Single Fruit Snack?" (By the way - don't play. You'll lose.)
Um, the only pictures from the grocery store are those on the surveillance cameras where they belong.
Cuz if you, in a bout of near insanity, let both kids out of the cart just so they'll stop crying already?
They might just box with each other at the end of the check-out line.
And? This might all cause Mommy to weigh the prospect of going through the liquor department and waiting in line with fighting children ALL OVER AGAIN.