Charlaine N - I think there are times when someone is thirsty at night, but the majority of cases a child will not need fluid.
If you create an environment where having a "sippie" at 11pm is condoned, then a "sippie" at 11pm is what is going to become the norm.
Kids are natural negotiators, and wonderful opportunists.
I have a simple "no" rule - no matter what is requested after bedtime the answer is no.
No, you cannot have custard.
No, you cannot have a slice of bread.
No, you cannot have juicie - and please do not call it juicie.
No, you cannot have a story.
No, you cannot have another kiss and a hug.
No, you cannot have a cuddle.
No, you are not having the light on.
My kids are sleep trained - not because I am a good mom, but because I am a mom who needs a break. However, not one night goes by with a request for something or some play on my emotions. If I give in once, I will be sitting giving custard/juice/extra blankets/cuddles all night.
I literally walk down the passage like a prison warden, clicking lights off going "no, what ever it is ask me at 7am tomorrow morning"
I realise it is harsh - but on the upside, I have an undisturbed sleep, I can go out and leave my kids with a babysitter, as they are not going to be crying at 11pm, I can sit and eat dinner albeit it at 8pm in peace, I can go to friends and put my kids down for bed there, and follow the same rule - I can be an adult person after 7pm.
I also know when my kids really need something - a sore throat needs a sip of juice, a bad dream needs a kiss and cuddle in bed, a fever needs a pick up, an extra love and maybe a sleep in mom's bed. I am not totally blind to my kid's needs - I just can differentiate between needs and wants.