So I get it, I'm a parent too...you don't always know your kid is sick. That being said I think I am being played for a fool.
The mom tells me yesterday that he was sick on the weekend. Ok now but didn't sleep much and to call her if he is not doing well. Yesterday he was off but OK, played well. Threw up at lunch but that is not abnormal for him occasionally if he eats too fast/doesn't chew enough (acid reflux, my 3 year old does this as well). Was crying for mom at nap, put him down and he slept for a while. Woke up and screamed for a while. Called mom, she came and picked him up. She said she wouldn't bring him tomorrow if he is not better.
Came today. He slept, looked better, mom said he seems fine but call her if anything is up. Seemed off a bit while playing but OK. At lunch threw up and changed his bum and his stool was looser, not liquid but loose. Put him for his nap knowing mom might be a while, called mom. She came right away but he had just fallen asleep. I told her I would call her once he woke up (she live one street over)
I know I sent my child to daycare before where you think they are all better but then they weren't. I hope she didn't send him even though he wasn't better as she had no other alternative.