That’s why I don’t like buying fluids online.
I love FCP, but I’m too lazy to ship my oil back
Might not be worth it for some to replace one annual oil-change kit. I have done this in the past, and it was a little unsettling. I have done it with more expensive parts, however, like Zimmerman brake rotors and pads. That was definitely worth it.
ECS Tuning has this program now, as well. Alternatively, you can get some pretty good oil shipped to your door when there are manufacturer rebates and skip mailing fluids back altogether.
This is profitable for them not necessarily because folks are too lazy to take advantage of it, but because if you buy expensive replacement parts, you are committed to having to repo your next set from them, and on and on. In my case, I have committed to being locked in to buying whatever rotors and pads they have for my Audi..
In many cases, these are replacement parts that will out live either you, the car, or your ownership of the car. Eg, if you get all new suspension components from them for an E36, are you likely to replace those a second time? I doubt it. In fact, your part might be discontinued when you get around to cashing in on the LRG. Maybe someone can chime in whether they'll order direct from Germany on your behalf, in that scenario.
It's a very niche market, and the LRG is non-transferable.