My guess is that “I’m excited and want a few for my friends and family!” is fine if it’s happening naturally, and that “I’ll buy a large number to pump up the sales” just gets filtered out. But it’s hard to say; the people who compile best-seller lists are presumably intentionally opaque about this. I wouldn’t sweat it too much as long as you’re not trying to game it.
My guess is that “I’m excited and want a few for my friends and family!” is fine if it’s happening naturally, and that “I’ll buy a large number to pump up the sales” just gets filtered out. But it’s hard to say; the people who compile best-seller lists are presumably intentionally opaque about this. I wouldn’t sweat it too much as long as you’re not trying to game it.