You are probably right, though personally I'm a bit wary of companies where you have to sign up and become a 'member' to buy from them.
I looked at this one's site just now, prompted by your post, not looking for anything in particular, and it wouldn't let me go any further without giving my email address. Maybe I could have made one up, more likely it would have said 'Verify the link we have just sent you'. Sod 'em is my view, there are plenty of other sellers to browse.
Edited to add: The only time I ever signed up with an online retailer was to get a £10 discount in exchange for receiving their monthly newsletter. When the first one was emailed to me I set up a filter for the address it came from to mark it as read and send it to my trash folder. Worth it for £10.