Damn Rules: Why am I the only one that understands them?

Okay, I sure as hell didn't write the book on playdate etiquette, and I swear I am not keeping a score card (oh bullshit who am I kidding, why am I always inviting over and never sending over? huh?? anyone??).
BUT it seems to me, that if One was to be asked - for a third time - to watch a Certain Mother's child - for a third time - while that Certain Mother was going to attend a Monday meeting at the school (practically next door to me One), and One left a message that said "yes, I will watch your child for you on that day you have that meeting, why don't you call me back and tell me WHICH MONDAY it was you needed help with and I will be happy to bring your little, secret-keeping, bug hating girlie girl home with me that day",
And then a Certain Mother does not return call for days and days until One has to in fact call her again and leave a message that says this:
"Hi there, Certain Mother who wants me to watch her child on some Monday, this is Gwendomama (aka suckah, aka your personal nanny-slave) calling again. I would really appreciate it if you could tell me WHICH MONDAY you would like me to take your child home, because Supergirl was in fact invited over to someone's house for tomorrow, and last week over spring break it was playdate central over here at my house, and if YOUR MONDAY is not tomorrow, I could really use the break. So please let me know soon."
And then a Certain Mother finally calls back to leave a frantic message that goes something like this:
"Hi Gwendomama, this is a Certain Mother, and I hope you have not accepted that other playdate for tomorrow, because MY MONDAY is, in fact, tomorrow. So, okay, call me and confirm, right? Now I will send you 7 emails to make sure that you are taking my child home tomorrow."

Well, it seems to me, that a Certain Mother might have acknowledged that One actually said 'I really could use a break' on her voice mail, and then a Certain Mother, who might just want to call One when the next meeting comes up, might just want to ask One's own child over for a playdate.

I'm just sayin.