Several of you have posted very generous replies. That's the true spirit of friendship. You take people with you because you're all friends. I've done this many times with friends who always show us a good time. Reciprocation is part of that equation too.
In his OP and several replies, John has described one friend who offered nothing on a recent trip and throws them all in the same lot. These guys invited themselves on not just one trip, but several. They apparently have no gear to share. I like several posts here, but Greg summed it up fairly well when he said riders pay for everything, gas, food, beer, etc. John has $50k in his truck the way it looks in his signature.
I'd commit to one trip as a trial and try it as I suggested above. Let them know early on what the "rules" are. If they buy food and gas you'll feel better about the trip. Bringing all the gear will ensure you're prepared, so that may the plus of being the ""outfitter".
We often visit friends in their cabins and we can not do enough for them. My wife cooks and I clean up. We bring stuff, all of the food if we can. We're going out on a boat next month with family who own a nice motor sailor. We could never reciprocate at that level. We'll try to do everything on that trip and buy them dinner on the way to or from.
Some people just need to be told what to bring. I'm organizing a trip right now for 3 friends. We'll take two cars including mine. The guy who's riding with me will pay for the gas. The trip wasn't even my idea but no one was taking initiative to plan the food. We leave in less than a week. None of them thought about water and there is none where we're going. White Mountains, East of the Sierras travelling through the Mojave Desert. Two of the guys don't know what food to take. One guy has special dietary needs due to his health and the other guy just hasn't given it any thought. The later, unprepared rider is not going to be ready. The way it's going I may end up just bring food for myself and my closest friend who's riding with me. He knows how to plan and contribute. These guys are 65 and older and have all travelled off-road before so it will probably work out fine, though one guy may be going hungry. :wink2: