Without having the opportunity to actually review this document, there is really no way of knowing how much protection, if any any at all, can be gained by such a document.
However, a document isn't going to offer much protection as far as preventing a lawsuit from being filed regardless of who generated the document.
The weight that such an instrument carries in a court of law, can vary depending on each states applicable laws. But generally speaking, no document is going to protect you from being held liable for damages which arise out of your negligence.
I'm not exactly sure what this group you're a member of, is offering to members, but it sounds like an informal group of people who are just looking for friends for them and their children to get together with and play.
So I imagine everyone takes a turn hosting the play activities in their own home, is this correct?
In other words, you don't have an official meeting hall or playground facilities which belong to the group and the group does not operate as a non profit organization, correct?
If this is the case, then it may be wiser to make sure each person hosting a play party, has protection under their homeowners insurance or some other policy that will cover them should someone get hurt on their property.
I'll give you an example of why your document may be nothing more than a false sense of security.
if a child was to fall in to a swimming pool and heaven forbid, drown. The amount of liability that falls on the homeowner, will not be determined by the document you're claiming everyone signs. What would be considered is if the homeowner was in compliance with all the state mandated requirements for having and keeping a residential swimming pool. Things like fencing, automatic closing gates, depth restrictions, as well as the conditions of accessories like slides and diving boards. All of these must meet the specific state and local codes. If one or more of these examples weren't up to code, and they in some way contributed to the accident, then your document isn't going to protect the homeowner.
What you may be able to accomplish with the document, is getting people to agree to going through an arbitration process if there is a problem or dispute, rather that head right for the courts. You may also be able to include a clause which states that everyone agrees that if a dispute does arise, that the losing party will be responsible for the other parties legal fees.
Now I'm not an attorney so don't take what I'm suggesting as any valid legal advice, I'm just giving you some things to think about.
But it isn't always losing a lawsuit that can put you in the poor house, it only takes having to defend yourself against one that can do that. This is why I suggest that you have members agree that the losing party in any legal action, should pay all costs.
