Yes! Simple and Pippin don't like me to go in the bathroom without them. Morris occasionally visits as well.
When Merry was alive, he and Pippin would take turns getting on the edge of the tub and peeking around, trying to see what was going on. Merry and Pippin have also fallen into the tub with me anytime I've taken a bath.
Pippin learned how to jump on the bathroom door so he can look over the shower curtain while I'm showering.
Other Pippin tricks include jumping on my back while I'm brushing my teeth, climbing in my pants when I'm on the "throne", and scratching at the guest towels hanging behind my head.
They also like to have the faucet turned on to get a drink, when I'm in there.
Closing the door doesn't help. It doesn't latch and they will team up on it to bust it open.