Pilots helping pilots? I don't get it. This guy didn't need any help; he needed to not be harassed by Capt. Respect My Authoritah!
If I see a pilot in uniform who didn't check in I would assume they are deadheading or non-rev, neither of which need to check in with the crew. It seems rather telling that this capt. just assumed he was jumpseating. I love all the replies from the Gojets brain trust. Just, wow.
The last part of the guy's post about professionalism is spot on. Try to open your minds a bit and think about what he wrote.