I think @stonysmith is correct here and goes to the heart of creating models via SW. The setup currently seems biased towards making your own stuff, primarily, with the production team working really hard to produce every model every time in an effort to satisfy the us the designers. This is a great thing and not to be criticized in any way.
But, if going forwards, people want to sell things in volumes large or small, and
sell them to other people then an extra mode of production or of judging the printability of models has to be added, one where the criteria are not 'can we print it (at all)?' but 'can we print this every time and to an acceptable, repeatable standard?'. As @stonysmith implies, as a designer you can take a little rejection, make the mod and reorder, as an external customer this type of setback might just mean 'Oh, I tried that Shapeways/3d printing thing and it didn't work.' Customer lost, future customer lost.
So, yes I would say that enhanced printability checks
should be the default for all models - after all SW doesn't know what is a one-off or a prototype for a production run. And then with the feedback (i.e. more communication) from these enhanced (stricter) checks, perhaps the option could be given to request to print on a 'best efforts basis', i.e the more on the limit designs, with the understanding that if they go on general sale 'unpredictable results may occur'.