Children at the reception?

I don't think that asking them not to bring children is bad. You could just say that the reception is an adult only affiar. One thing is, is you could provide some type of childcare that way you know where the children will be, or the other thing is to make your reception more child friendly instead. Add something like a kids table which could have coloring book, crayons, and other such things to keep children interested on other things than stressing you out at the reception.

Its your wedding, so you can do what you want but you would be limiting your guest list because it is often hard for people to find babysitters, especially those who travel, for their young children. A wedding should be for all to enjoy, most people with kids usually leave early anyway.

I think that since it is your wedding you should ask people to do what you think is most appropriate. However, you have to remember that some people might take offense to this, and there is a good chance (if they are not your closest friend) that they wont even show up. What makes it so not "kid-friendly" anyway?

Maybe you could have a room inside the building where you are having your reception and hire a professional to watch them while the parents are at the reception.

I'm not having children at my wedding either. On the RSVP card, I put Please remember the reception is 18 and older, but children are welcome at the ceremony. I'm not having children there due to a space limit and theres a bar in the building next to the hall I'm using. They are not allowed in there and I can be held civiliy and criminaly responsible.

I also put a separate paper in the envelop, stating that I have responsible teenagers available to watch their children while they enjoy the reception.