Indeed... but in this particular case the "/" was added in the middle where it has no effect:

http://onstartups.com/home/tabid/3339/bid/6119//6-Y-Combinat...

http://onstartups.com/home/tabid/3339/bid/6119/6-Y-Combinato...

Notice the "//" before the filename in the first version.

The point is that we don't want duplicate content, even if it's at slightly different URLs.

I think the counter-point was that it may actually be different content. How often that is the case, I don't know, but assuming it will never happen doesn't necessarily seem like a great idea.

Maybe the system should actually check what's at each page.

And you should read more carefully. I did not suggest the thing you say is a bad idea.