I allow them to come with colds and I don't require a clear runny nose. I'll take any such colour. Kids will have colds, as long as they can still do all of our activities and participate, they're welcome here.
I don't allow fevers.
I had an un expected day off yesterday because everyone is sick with fevers. They're just passing it around right now. It happens every year at this time.
You're right, it's frustrating when we're dismissed. Especially when we feel that we are being helpful. Unfortunately, most parents don't see us letting them know their child is sick as helpful. It's a pain for them to stay home from work.
I let the client know, but that's it. If they don't believe me, then that's their issue. I just deal with it as it comes. I don't always need to be right. It's not my job to be right, it's my job to communicate well.