Always an awkward one this, we could all sit back and let someone else do the work and then sponge of them, but, as you say, telling people to politely sod off might come across in the wrong way! I personally don't think research time is any different to model construction time, if you made a model you could then sell it as an asset, why not think of intellectual rights in the same way, after all, if you had all the information dropped into your lap at the beginning you would be a lot closer to finishing the layout. Also, to me, research is another facet to the hobby, useful for understanding what you are modelling and why.
Mike.