We have tested this dozens of times, it works 100% for us, on all computers, and this is over months.
I'm not doubting it may not be working for you. Perhaps the user in question visited our site before from another link and that person go the credit. I dont know but we give away a ton of free snipes so it is working.
As for links on webpages and such they just dont produce the kind of results most peopel think they should. Most banner ads get 1 click in 1000-2000 views. Then out of that maybe they get a 1% response rate or purchase. So that's 10000 views for 1 sale on a god day.
We simply read that field, if it's entered correctly the database adds 3 snipes. It's honestly like 5 lines of programming. It costs us roughly $2-3 for a support reply. Thus 1 support case may cost us a few dollars. Why on earth would we try and jip someone out of 3 free snipes. It makes no sense. So that's not the case. So that leaves the programming in question and since this is really just like 5 lines of programminmg that we've seen tested over and over that doesnt seem likely.