Originally Posted by iwebslinger
Does a B or higher fare (YR2, D, F) on hold on a international flight affect the flight inventory?
Yes, although a carrier might discount the probability of your being a no show at a different rate than they would for a non-refundable fare.
A few times I've been in a party of two and there was only one seat left to sell. We bought one, which reduced the inventory to zero, and had to waitlist the second.