My MIL drove me crazy throughout my pregnancy with this. She never once asked me if I wanted her there but told all her friends and family that she would be there. The first I knew of her plans was at a freind's birthday party when she said she couldn't wait to see her grandchild being born. Its lucky that I was too busy picking my jaw up off the floor to voice my opinion of this plan because had I said what came into my mind it would have been rude and offensive at best. One of my freinds asked me about it later and I said no way - which is when I found out that she had been telling all and sundry that she was taking time off work to be at the birth.
I was really offended that she would go ahead and make assumptions like this without even asking me and more than a tad suprised that she thought that I would want her to be there. In fact I don't think that she even considered what I wanted because if she had she would have known that she wouldn't be invited. It was all about what she wanted and she just assumed that she would be able to get her own way. Since she has told everyone she would be there without even bothering to consult me I repayed the favour by telling everyone that she wasn't invited and wouldn't be there and told DH to make it clear to her (childish I know...I should have told her upfront but I was so annoyed with her!!).
After my mother died MIL suddenly started harrassing me about being at the labour because my mother couldn't be there. My mother had never planned to be there - she knew me well enough to know that I would prefer as much privacy as possible. It really upset me that MIL would try and take advantage of my mother's death to push her own agenda and I became even more determined that she wouldn't be at the birth.
One of the girls on bellybelly told me about her MIL pushing her way into the delivery suite so I decided to go one step further and not tell anyone when I went into labour. DH was a bit ****d off about this but after lots of arguments my way prevailed (SIL didn't invite MIL either but told her that she was in labour and MIL and SIL's MIL waited outside and pushed into the delivery suite within 5 minutes of the birth - which kind of ruined SIL's quiet time with her baby - after this DH came around to the secret labour concept quite quickly).
As it turned out I didn't go into labour until some time after my waters broke so we ended up having to tell people that I was in hospital. At some point after labour began I heard her in the corridor outside but DH and the midwives got rid of her. I'm still a bit astonished that even after months of being told by her son that it was just going to be us that she still tried to get in there - its really an amazing display of insensitivity.
I think that the annoyance certainly stressed me out at times and caused a few arguments between me and DH that I could have lived without. I'm really glad that I stuck to my guns because I would have found it incredibly stressful to have her there.
My SIL also faced the same dilemma and dealt with it by saying that she was only allowed one extra support person and her MIL would be insulted if she wasn't allowed. It wasn't true but I thought it was a great excuse that avoided insulting anyone. I feel a bit sorry for MIL because no-one wants her at thier delivery but she's not the kind of person who you want around at a time like that. Maybe if BIL ever has kids she'll get lucky then but I doubt it.