Citation from blog: > The fact you hold a prior art in your hand, doesn’t mean much. The patent will still prevent you from importing/selling etc of the “infringing” stuff.

Could you please explain this to me? Let's say, they (Chinese) patent some complex part of my open-hw 3D printer, how this prevents me from importing parts of my 3D printer from other countries? Let's say from China. Company, which originally patent trolled me, must sue me first, no? And they care about patents? Since when?