huh? Either get a sitter and chaperone, or don't go.

I guess it depends. I wouldn’t change plans around it either way. If you have a play date at the zoo every Tuesday, then I wouldn’t skip it because older sibling is also going to be there on a field trip. But if you never go to the zoo, I wouldn’t make a special trip there on field trip day.

Your child will be assigned to another actual chaperone for the day...but want to hangout with you making it awkward for the other parent.

Wasn't there a recent thread about this? I think the consensus then was also that it's not a great idea.

Our school explicitly tells parents not to do this for all of the reasons already given.

Omg let the kid breathe without you for one day. Will be confusing and disruptive.

Don't do it. Its not fair to both your kids. If you want to chaperone leave your younger kid at home so they are not a distraction.

I think it's helicopter parenting. Leave your 3rd grader alone and let him have his field trip experience without his sibling.

A newborn that is strapped to your chest is one thing. A mobile toddler is another. I don't see what good will come of it, other than distracting your kid and possibly being disruptive, especially if the toddler wants to interact with the older sibling. If you want to take your toddler to a museum, do it on your own time.

If your third grader really wants you to chaperone one of her trips, just get a babysitter and do it for real once a year.

I wouldn't care if you do this, but I can't imagine why you need to? I could see one of my kids causing a problem, wanting to come home with me, or wanting me to buy him something (that the other kids in his group aren't getting), or somehow just being disruptive in a way that wouldn't be the case if I weren't there. Seems like there's no benefit and a small chance of causing a problem, so why?

What's the point OP?

I wouldn't. Parents shouldn't "drop in" on field trips. Either be there as a responsible chaperone or don't go. It can create confusion and disputes the flow of the field trip.

Check with the Teacher and see how they feel about it.

I'm a SAHM with 2 kids in elementary and a 2yo. I can't chaperone field trips because of my little one. When my kid was in kindergarten, there was a field trip at the local nature center and the kindergarten teacher told me it was ok for me to come and walk around with my then newborn. I have seen parents stop by the zoo or Museum of Natural History without being a full chaperone. I'm assuming they couldn't take the whole day off but came for part of the day or lunch break.

Would it be frowned upon to go to the field trip venue with a younger sibling?

I won't take my kid home with me. I will most likely just walk around with my 2yo and say hello to my now 3rd grader.