This was brought up in Nicksmom's post, and I think (if I can be so bold as to put words in mouths) that the thought behind the words is being misconstrued. I say this from my own experience, so feel free to correct me if I'm way off base.
Ima made the rough analogy about 3-4 days vs. 7-9, and several people jumped on her about it not being about the number of days that matter. I agree . . . it's about the attitude behind them.
An example: A month or two ago SD's mom wanted to take SD during one of 'our' weekends for a full day to attend a family party. We said sure, and she went. A couple of weeks ago we asked if SD could come with us for a few mere hours to attend a dinner with out of town family, and BM went on a tirade about stealing SD during 'her' time. SD did not go.
To me, it's not about keeping score - it's about what is good for the goose being good for the gander. If Nicksmom's SD's mom would only 'allow' SD to be gone over Thanksgiving break for 4 days during all the years she was custodial, why does she think she has the right to demand more than that now that the shoe is on the other foot? Because she misses her daughter? Well duh - I'm sure her father missed her as well. My theory? Just like the hockey game, and just like the party with my SD, because it is what MOM wants . . . and so it should be.
I have to say this is one of the hardest things for me to deal with when it comes to SD's mom. She can completely shoot down a request we might have but come back 10 minutes later asking for the same and more, and pitch a fit when she doesn't get it. It's almost mind blowing.
So I don't think it's just about keeping score. It's more expecting that the other parent acknowledge that they are asking for the above and beyond. Acknowledge they are asking for something they always refused when they held the 'power card.' Possibly, understand that the other parent wasn't really being so unreasonable with their requests, now that they are standing in their shoes. Or to make it simplistic, recognize that to get you need to be willing to give as well.