Thanks, everyone.
Bill, my BIL works during the weekends and has Mondays and Tuesdays off. I'm not entirely sure why they don't bring my niece over on Saturday evenings after he's off work, or even Sunday mornings so that my MIL might have more time to run errands and decompress, but I try to just shrug it off as not being any of my concern.
Honestly, I have no interest whatsoever in scheduling a regular time for them to go grocery shopping and babysit for them. I don't consider it my responsibility, even if that sounds harsh.
I'm happy to help on an occasional basis, as I enjoy my niece and I have fun with her, but my MIL is the one who has signed up to watch my niece all weekend long, not me or my husband.
I do feel guilt about it, but we really don't ask my MIL to watch our son even half as much as she has always watched my niece, and as I mentioned, she has been the one who has practically shouted and waved a sign about how much she LIVES for spending time with her grandchildren.
As for my husband and I, we love our niece and enjoy having her over, but we're not trying to sign up for a regular babysitting position for her.
For the moment, we live in a very small, cramped one bedroom apartment (there is a second office room that we've had to use for storage), and our living room literally serves the dual purpose of living room and nursery.
We're also pretty stressed right now, trying to buy a home and dealing with investors and banks, and my husband's job is really stressing him out.
So, not really the best time or place to have a four year-old jumping around while my son is crawling around on the floor or trying to sleep...
Tromboneliness, the problem with not answering the phone is that, while I generally try to keep my distance from my MIL (although we do exchange some very simple, basic favors and help with each other when needed), my husband talks to her literally every day on the phone, so there's never any way of knowing if she's going to hit us up to babysit on the spur of the moment.
Thankfully, my husband has as little interest in being a regular babysitter as I do, so he doesn't mind saying "No" when we've had too much, or just need our personal family time.
At any rate, I think it's worked itself out for this weekend, which is nice. Like I said, I feel a lot of guilt for sounding so callous, but really...
Once in a while, when a need comes up, I'm happy to help. On a regular basis, it starts to get annoying.
