To troubleshoot, try printing the referrer url. E.g. just put ${http.request.referrer} and see what it spits out.
One possibility is that it's not actually all lower case.
Try this as well:
<#if http.request.referrer?lower_case?contains("userregistrationpage")>I find that ?lower_case, if perhaps not in this case, works magic in a lot of other cases, because you can always ensure you're comparing two fully lowercase strings.
For example
<#assign lookfor = "userRegistrationPage"/>
<#assign ref = http.request.referrer/>
<#if reflower_case?contains(lookfor?lower_case)>
