I just started my 3rd trimester so this might come back to bite me in the butt one LO make's his/her appearance, but I wanted to know how you handle picking battles with your LO's.

Yesterday we were at my IL's house for dinner, and my SIL was there with my niece who is 20 months old. Toward the end of the night, when it was time for PJ's and then later again when it was time to put on her shoes to get going, niece started to fuss and whine and didn't want to stop what she was doing to put her jammies on, and later, did the same thing and threw herself down on the floor because she didn't want to put her shoes on. SIL waited her out on the PJ thing and eventually coerced her into putting them on, and just gave up on the shoes.
On the car ride home, DH was miffed, and asked if I would have forced LO to do what I aksed or given in at that point. Not once did anyone say to her "it's not okay to behave this way" or anything like that, and were it our child, he said he would have explained to the little one that throwing a fit isn't acceptable, and you have to do what mommy/daddy says.
Admittedly, she is the only child (for now, her brother is due any day now!) and isn't used to not getting what she wants (especially at Grandma and Grandpa's house!), but is it worth it to make a point to a 20 month old or do you just let it go?