While not "necessarily bad" it can become a huge PITA. End-users are just that, end-users. They dont pay for anything and as such have a wealth of opinions about how the system should work (without regard to how much the system will cost to build).

I don't think it's my job to get the system right for the end-user. It's my job to get the system right for my client. Now if the client doesn't consult the people he is going to force this new system on, then I can not be held responsible for his failing.

It has always been my policy to get one or possibly two contacts at the client site. All requests come through them and anything else, unless otherwise instructed, is filed or sent back to them without me dealing directly with the sender.