For me, it would depend on the services they rendered. I don't see a need to tip them just for being there - that's their job. But for exemplary attention to me wants and needs I would consider a tip, and if they had indeed helped my in some specific way(s), I would definitely tip nicely. In many ways they are like a hotel concierge, providing help, advice and services when and if I want them. If I take advantage of that help, a tip is appropriate. If I don't, no tip just for being there.
2004 American Tradition; 2014 Buick LaCRosse
Homebase in the Ocala Nat'l Forest near Ocala, FL