Yep, you can now lock any gate just for pets in addition to the usual 'my household, me, etc.' options.
Speaking of gates...since I got Pets I started a new family with just a couple cats. It's been a while since I've played Sims, and I wanted to start slow getting back into it.
After I got comfortable, I copied my rich Bridgeport sims to the library and moved them into a horse ranch in the new town. Since they're 4 and 5 star celebrities, the paparazzi immediately started annoying me. I fenced in the whole place and locked everything to my household to keep them out.
Since I wanted to concentrate on my couple training their horses, I hired a maid. The maid couldn't get in the gate. I unlocked the gate to let her in and the paparazzi flood followed. They were interfering with everything I tried to do with the horses. Grrr.
So, I thought maybe a butler would work. I got a basement put in to make room for the butler, hired one, and they were locked out. I've unlocked the gate to let her in and locked it after her. Will that be a problem? Is there any reason she would have to 'get out'? Like I said, it's been a few months since I played, so I'm really rusty.