[d_j_s]

That's not correct, you as a user run a snippet of leadlander js code on your web page. This code has no access to the cookies on a leadlander domain.

I've worked on a similar tracking snippet/system for http://www.projectcounter.org/ and this was one of the first things we attempted.

If you block the leadlander domain(s) the script will obviously not run and also consequently won't be able to send fingerprint details back.