I think I've already run into cases where displaytypes or such were made too DWIM and I've regretting it because a more sensible action became available (and you can replace an error with a good new behavior but backward compat prevents you from easily replacing an ill-advised DWIM action with a more consistent action).

But perhaps a good compromise would be to have node viewcode page include the above link along with the error text so that you could still easily get to the somewhat related "code for the node" but in a way that wouldn't confuse people into thinking that the code actually is part of the node they requested and that could be changed down the road.