refblock (dot) com in referrer stats

I am getting refblock (dot) com showing up in my referrer URLS in my stats. A fair bit to be honest (i.e. enough that I notice!). Now I totally understand what refblock does (hides the linker's URL from my referrer stats) and sort of understand why someone might do that in general. However, I can't work out why someone would be linking to a/my bingo portal/affiliate site using this!

I am not worried, just curious as to why someone might do that. Do others see this in their referrer stats?