My parents took us all to the Dom Rep last christmas. My kids were 12mths & 6yrs and my sister's 7 & 9.
I took a few pressies for them to open there and told them Santa knew we weren't going to be at home and we wouldn't be able to carry anymore things in the suitcase. That was true obviously! We did however pack up their sacks to they had main pressies at home but if you do want to avoid this then simply tell your kids instead of sending a lot of money to Santa you are going to spend it on a holiday instead! You could always gage a reaction by speaking to them before you book to see what they think. As long as they have something to open I dont think they will mind at all. It was the first time I have ever been away at Christmas and it was fab! Christmas carols playing while you're sunbathing and all the decs up, just like home but hot. I would go for it, it's not something that has to be done every year.