Sorry about not getting back to you on the other thread...
I'll flag this to the team. This was originally meant to be a small perk for forum users but if the codes are getting posted elsewhere on the t'internet, then I agree it defeats the point...
Be interesting to see if you find it any easier to get a screening if we stop posting them here first. The newsletter goes out to thousands of users. I wouldn't be surprised if the emails go out in batches, so if you're not in the first batch, the codes could well be being snatched up by legit TF newsletter subscribers... I'll enquire about the batch thing as well.
Keep you posted here.