I just need to roooooll my eyes

about my MIL here.
Background: Dh's sister is pregnant with an unplanned baby in August. She's not sure yet if she will keep the baby and get married to her bf (I don't think he wants to get married until later) or give the baby up for adoption. My inlaws want her to give the baby up for adoption for various reasons, including her maturity level and the fact that she's Christian and her bf is not.
Anyway, the inlaws are planning a vacation since FIL needs to use up vacation time by September. They were talking about how we need to go on vacation (it'll help us get pregnant!

) and then all of a sudden they are asking about us going on vacation with them.

Umm. I haven't gone anywhere "big" with my Dh since our honeymoon 4 years ago. If they want me to destress so that we can make a baby, how in the heck is that going to happen if we go on vacation WITH them!? We get along with them, but I guess I am just not cool with the idea of going on vacation with my inlaws. Is that just me?!
So what is really making me

is that it JUST NOW dawned on my MIL that "Oh yeah! SIL is due in August" so she calls to find out the exact date and she is due August 20. They want to go on vacation for a week starting August 19. My SIL told them to go ahead and go since the due date could be wrong anyhow. So she said they are going. I can't believe it!
1. That she didn't even know the exact date her daughter was due.
2. That after starting to plan the vacation it took her DAYS to remember that her daughter was due in August.
3. That she is still going to go!
I mean, if SIL does give the baby up for adoption, she is really going to need some support at that time. If she doesn't *shrug* I guess MIL figures her bf will be there and that is good enough?
I just think it's strange. I really can't believe she just "forgot" that she was due that month. DUH.