For me, the flipping just sucks for newer or quieter members. If you have people willing to pay exorbitant prices, I guess make your money. If it’s made on the backs of others, shame on you (obviously situations vary).
But for new people just trying to ingratiate themselves with the community, but can’t attend meetups and aren’t comfortable constantly asking questions/private messaging, it can be difficult to ascertain what the heck this market really looks like and who are good chippers to deal with (yes I get the irony).
Personally I think you can avoid flipping and increase the reach of the private sale community by creating some general suggestions and a status quo. My tag line states that anyone I buy from has first right at same cost when I sell. And I attach the same thought to sets that I let go from under market value to dirt cheap. It makes for a great little spiderweb network, which allows others to get chips in their hands they might not, and me to pick up chips I might not otherwise. Sure I take a considerable loss upfront, but if you’re truly looking at it as renting chips and not an investment, it works amazingly. I get that the well established chippers don't need any impetus/gimmick like this as they have an established rapport with who they want to work, but it's helped me a couple times.