Last year, my 3 YO went to the kids club once so DH & I could go to Palo. He hadn't been left w/anyone other than family prior to that, and he hadn't started pre-school yet. He wouldn't go any other time (even when they did a Buzz Lightyear theme event. Buzz is his favorite). We were paged to come get him, but when we got there, he seemed fine. We did pick him up b/c his brother was a monster in Flounders and our night was ruined anyway. I'm hoping that this year will be better. He's been in pre-school for a year, and will have a friend cruising w/us the same age. Best of luck.
Woobie