Yes, that is a potential problem. I'm lucky in that I have a captive audience of sorts, a Facebook group where the manufacturer of this product allows me to post when I have it. So I can stipulate in there that anyone who wants to sign up for the subscription plan MUST ORDER IT BY ITSELF! And of course, someone inevitably will disregard that, but it will be a small enough number that I can deal with those orders individually. I have to do it already for this product, as I never know exactly what mix of formulations I'll be getting each time it comes in.