I've come close to doing what you did many times. Luckily, I always have one last close look at almost any poster I bid on, and certainly with one that's going to 'cost' me, before I bid. It's saved me many times.
'Flaws' I would consider 'history' that wouldn't deter me from buying an item.... fold lines, censor stamps, show dates/times
'Flaws' I would consider, well, flaws that I would try and steer clear of ... pinholes, rips, tears, excessive fold wear, writing not related to the dates/times
My two cents anyhow.