ORIGINAL: TheDriftingNarwhal
You have to understand how the applications work.
If something looks like an attack - even if it isn't - it will try to block it. If there is no way to block it, perhaps it won't allow you to continue to the page.

As far as the ''Superior'' Norton, perhaps rather than Norton being ''smarter'' than all the rest, perhaps it is simply a different form of security software that doesn't scan for that type of attack and therefore does not display an error.

And this is most likely a block that is consistent among programs that actively block such issues. No problems with this, however I can say that it isn't the fault of the web developers or advertisers (morerc.com seems legit but not sure there) but more likely a failed implementation using code logically written accidentally in the same form of an attack.

It isn't an attack most likely. Think of emails - images are blocked unless you know who they are because images can lead to attacks. Of course most images are not attacks.. but they are prevented anyways.

This problem however is a more unlikely coincidence in the code and is therefore blocked with more effort.

It's pretty much just the software doing what it's supposed to do, it can only go so far to determine if something truly is an attack.