Not a parent yet, but I’d agree with many other posters here. Squeaks are okay, understandable, and even expected! Sustained bellering, talking, and other noisy disruption is not, and should not be tolerated. Take 'em out immediately! The longer you wait, the more impatient others get (no matter how charitable they are), and the greater the embarrassment when you finally do take control of the situation.
Taking them out immediately and consistently sends the following message:
“Something I’m doing is not acceptable and the consequence is being removed from church.”
If they act up out of need, it should give you a chance to work on the problem immediately (hungry, has to go potty, has a tummy ache, her shoes hurt, sound system too loud) or for next time (don’t sit near scary man who stares and grins, make sure she had her nap).
Now, if they don’t want to be there and they act up in order to be removed (or get your personal attention, or others’ attention), then you need to send the message that it is more desirable to be in church behaving appropriately than it is sitting out here with an angry Mom or Dad, and that being “out here” means we still have to kneel and do all the things we would do “in there.” Maybe the consequence is losing a favorite toy for a few days, or not going to Show-Biz, or the threat (or actualization) of “getting something to cry about.”
If they’re bored (most likely), then keep them engaged on the Mass! I never got cheerios and dolls to play with. I was allowed a couple of children’s religious picture books. Mostly, I remember these things:
0.) We ALWAYS went to Mass. Not negotiable.
1.) I always had to sit between Mom and Dad, usually with kneeler down. There was no escape to the aisle or under the pew.
2.) We always got there early enough to sit in the front row, so I thought everybody was watching me, even the priest! It was OK to stand on the kneeler to watch. Coats and purses went on the unused pew in front, so I couldn’t be distracted.
3.) It was expected that I copy Mom and Dad in standing, sitting, kneeling, sitting, walking to communion, and singing. When the priest talked forever (homily), it was OK to rest my head on Mom for awhile. It was OK to whisper or get Mom’s attention EXCEPT during the Eucharistic Prayer.
4.) My folks made a game out of following along in the missalette by pointing to the correct page number, well before I could read (or count). I could recognize shapes and blocks of text and caught on to the familiar pattern of flipping pages. In time I tried to trace my finger while the text was spoken, and while I didn’t get the meaning, I was at some level reading along. I think this helped accelerate my reading skills and vocabulary. To this day I am haunted by the word “recompense”

5.) If I got too noisy, talkative, or wormy, I would be swiftly taken out, and I “knew” that was not good. I would also hear about it all the way home, and maybe the next week, too.
Maybe that’s a lot of structure for a kid, but I think it served me well. I caught on to the Mass and the prayers pretty quickly, and because of this (or in spite of being sandwiched) I signed up to be an altar server at the first opportunity, which didn’t hurt me any! It too kept me very engaged and learning.
I can’t BELIEVE what happened at the Milwaukee Irish Fest Mass this year. There are thousands of people in this ampitheater (which projects sound well), and lots of families with kids and babies which make the occasional local noises. But a couple with 2 kids and a baby sit almost directly a row behind us (knee level at our ear level) and let one of their kids scream at the top of her lungs for the greater part of the 1h45m mass. It wasn’t the baby, either. It was about a 2-3 yr. old girl who could form simple sentences and was clearly big enough to know better. They let her holler through the scriptures, the Gospel, the homily, the intentions, and the Eucharistic Prayer. About the only time she shut up was when people were singing, because I think she knew she couldn’t compete! And then during some announcements after Communion, she kept asking “Over? Mommy, is over now?” There were two parents, they were reasonably close to the exit and NOBODY was seated in their way to the stairs, so there was really no excuse for one of them not taking her out at the first (or second…or fifth…or tenth…) sign that this was going to keep happening.