Sure it is "by design" or "as implemented"
The problem is in my opinion still a valid one. If you write code which goes to a customer, the customers machine will have most surely a virus scanner ( even if we are writting software for industrial usage, most of the customers try to get a free scanner ) .
So even if we can exclude it from being scanned on a developer or build machine, a customer could still not use an obfuscated programm with ease. It just does not look good if you create a program and a customer gets an antivirus warning.
Also for security resons it would be good if the file could be scanned - but it should not think that only because it is obfuscated it is a virus.
Think about it - should we tell a customer: Don't use this or that virusscanner together with our product, it will say that out product is a virus but it isn't? If you exclude it maybe a virus can get attached to the file so for this files do not use this virus scanner, use that one?
Are there really virsues written in .net languages? Always thought they where written on a level nearer to hardware ...
I understand that it won't be easy to tell which programm is a virus and which is obfuscated to protect intellectual properties.