By the same token, you have no idea if I am seated in the bulkhead for medical reasons. Quite a few years ago I suffered a pretty severe injury to my hamstring, but had to fly shortly afterwards. I was on crutches, had a support bandage under my skirt, but once the crew had stashed my crutches for me, there was no visible reason you could have seen that I shouldn't have been ok with you scrambling over me. In reality, anyone that inconsiderate could have caused me incredible pain. Had someone asked (before deciding it was their right of way) I could have pointed it out, and in all probability said 'sure, as long as your step over my leg very carefully' but someone who determined that it was 'single class' and therefore all fair, could have really hurt me a lot. Fortunately, no one was that inconsiderate on this flight.