Too "Busy" to Potty

I've been having some trouble logging on because things have been so hectic now that I am officially in the full swing of things at work (and nothing has changed at home- still a Full Time mom), but I assure you that my life has not been any less eventful than usual. Where do I begin???
I'm not sure if I've mentioned that my 2 year old daughter has been potty trained for a number of months now.... I have only her sitter to thank for this because I would not even know where to begin with that, but I digress. So, she's GREAT and tells me when she has to go even when I've completely forgotten that she is not an adult and can't just go into the bathroom and pee on her own. Unfortunately, she does not do the same for her sitter and when I went to pick her up the other day she is wearing pants that are clearly not hers and running around like nothing is up. When I ask her what happened and why she is not in her own jeans she says "Nana pee pee". The cutest part about it is that she points to herself like I don't know who Nana is. Poor sitter! I ask her what happened and she tells me that she had asked Liana if she needed to use the potty and she insisted she didn't (but really she was busy playing and couldn't be bothered with using the potty). She found out the hard way when later she went to get her to tell her that this time she "had" to go just in case, but she had already peed everywhere! The funny part (but maybe not so funny at the time for her) is that it was clear that it had not just happened but Liana kept playing as if nothing had happened without a care in the world. I remind Liana that she has to tell her sitter when she has to pee, just like she tells mommy and she says in her cutest voice "Yes Mommy!"
Meanwhile, I called the sitter yesterday to tell her that my hubby is running late because he got out of work late and she tells me that she peed again!! OMG! I don't know what it is, but when I tell you that the ONLY time she has peed while with me was when she was in "time out" and I thought she was saying she had to pee so that she could get out of time out. Boy was i surprised to find that puddle of pee and all I could do was blame myself.
So, I call my hubby and remind him that yelling at her for peeing is only detrimental and just not to make a big deal about it- "just remind her that she has to tell the sitter when she has to pee". "I know I know, I just can't understand why she doesn't do that with us". We're certainly not complaining, but just feel bad that on top of all the other stuff she's doing, she now has to worry about our daughter wetting herself because she is so engulfed in playtime.
So many other things to chat about but I'll leave you with that for now.... any suggestions on how to get my daughter to tell her sitter she has to use the potty???