For me, it's more like:
"Hey family, I'll be at Disney again this Summer. It's the only time I plan on coming to Florida this year. Here's the dates I'll be down there.....
If you want to COME TO DISNEY to see us, let us know and we'll expect to meet you in the parks. IF NOT, well maybe you can catch up to us when we come down there for vacation another year. 
Now, I WILL go visit relatives in Florida before or after a Disney vacation if I can tack on the days and they room and board us. But I'm not going to cut a single second out of my trip for them. Great if they want to come along and try to keep up with us.
For example, this summer, I'm going to Disney from June 6-the 14th. I have a cousin and his family coming over from Tampa to meet us for one day in the parks and then AFTER our trip, we'll go spend a couple of days in Tampa with them. The Tampa days were added after the fact and are only because they'll provide room for us. We might hit Busch Garden, Ybor City, or some Gulf Coast beaches, but this isn't to take a penny or second away from the initial trip I booked.