Okay, so this is the test of “the only stupid question is the one you don’t ask” saying.
But does it?
No-one ever mentions it does, and I’m aware cross-lining is partly done to even out porosity. But it strikes me that lining paper is massively porous and will suck out paste from your top paper in an instant, making it difficult to adjust. So will anything bad happen if I give it a coat of HB primer-sealer?