The pickup screen prevents anything that big from getting sucked into the intake tube. I guess if you had enough stuff in the pan it could potentially cause oil starvation.
I have had a lot of trucks and 4Runners with 22RE's and I also had pieces laying in the pan for who knows how long. Still got tons of miles out of them.
Thinking about it, I don't ever remember having the pieces suck up on the screen. Pretty much stayed toward the front of the pan where they fell.
