Have been a member of P&B for a few months however not really one for posting. I appreciate this may look slightly scam-like given my low post rate.
I bought a Oneplus 2 in the recent general sale and have since received three invitations to share, all I need from anyone interested is their email address and I will forward one on to them. There is no link to click on or anything, you can navigate to the Oneplus site of your own volition. Whether they are used or not doesn't affect me in any way, I just thought I would offer seeing, as you quite rightly point out, they are sought after.
ETA - They expire on Sunday so would need to be used before then.