Another question related to this -

My older sister just gave birth yesterday so by the time the wedding comes around she'll be nearly 4mths old. We are having on the invites "sorry we will not be catering for children" or gentle words to that affect simply because we can't afford any more guests and the menu will not cater for them (not big restaurant for them to run around either) plus ppl drinking etc its not right atmosphere for kids etc etc... we don't need to have a reason really we just want ppl to respect our decision as it's our wedding

My sister will no doubt ask or expect that her 4mth old is invited if she is b/feeding at that stage (possibly still) so does that mean we really do need to invite my new niece because she is considered immediate family?? i mean, 2 of my friends have young children but they are about 7mths and 16mths old. they understand they aren't bringing them and respect us for that besides they want a night away from the kids and to drink.
if my sister says "Lucy is invited of course isnt she?" then what do i say? i'll have to say yes won't i? cos shes my sister and little niece? would it be wrong if we said "can't she stay with your MIL?"
what are your thoughts????? I asked Mum and she said "yes of course you have to invite her because she'll be breastfeeding her"

i loveeeeee babies and kids of course and do not want to offend anyone but if she can bring her kid wont that make my friends think "how come we couldnt bring our kids???" or will they understand because its my sisters baby???
I dont want a crying baby all night!!!! and during ceremony too....... will that happen????