how were you forced?

wow... you couldn't give up one day to allow her to take a few hours' break from the 24/7/365 job of being a parent? do the world a favor - please DO NOT breed, *ever*!

that's not right. you paid for that trip you should get to relax instead and your sister and her boyfriend do the babysitting.

So, let me get this straight: You have enough excess in life to take eight people on a cruise, but you're complaining about watching five kids for a short time to give the parents a break? People who definitely need a vacation more than you do?

Sack up OP. Quit being a doormat.

Somebody needs an abrasive side.

Everyone calling OP selfish and saying that they pretty much are obligated to babysit needs to shut their mouths! My parents always try and make me watch my little sister or take her places with me when they have no intentions of going anywhere and get pissed when I say no but she's not my child and I'm not responsible for her. Just like OP isn't responsible for her nieces. OP's sister needs to do her job and be a mother to her children whether she's on vacation or not that's kinda the point of her giving birth to them. It kinda sorta makes her responsible for them. OP, step up and tell your sister no, you came on this vacation single and child free and that's how you intend to spend it that she's needs to get back to the room and take care of HER children.

Sorry, but YDI. If you paid for the cruise, they don't get to tell you that you have to babysit - but they can ask, and it's your responsibility to say "No" if you don't want to.

That is entirely your fault. You should have said no! You paid for the trip! They are lucky they got to join you on your fabulous vacation.

Why did you do it at all?