Every item in the shop is a number in the system, so when this website says a board is free on Thursday, a board is free on Thursday. Nobody has to walk down and find out.
It is the whole reason we put the hire online. The old arrangement was a diary with pencil in it, and twice a season somebody arrived for a board that had gone out an hour earlier.
If the rack is empty on your dates the site says so rather than taking the booking and apologising later.