Jack_Diane_Freedom wrote:
Just don't tell them when you are going away. Just go..
X2.
Your post reminded me of my cheap Great Uncle. Long ago when I was a teenager my parents had a boat. It had two inboard engines and it would cost my parents a few hundred dollars to fill the tanks before a weekend out (and this was back when gas was cheap). One time they asked my Great Uncle to chip in and bring food for the weekend. He showed up with one package of lunchmeat. Needless to say he wore out his welcome quickly.
Only you can decide if your enjoyment of your guests outweighs the potential for their freeloading. If it's not worth the stress then put the word out that you'll be traveling alone (or with your spouse only) from now on.