Is a Hostelworld Gold membership locked to one particular account, or can it be used when make booking from separate accounts to get a discount? If the latter, then does Hostelworld invalidate cards that are shared by 'too many' accounts?
I don't have a Hostelworld membership, but I emailed them to see what the official stance is (without anyone risking getting their card invalidated).
From Louise Clark on the customer service team:
So it looks like the answer is: enter in the membership number on as many bookings as you'd like from as many email addresses you'd like. :) Happy traveling!