PVA on plastered walls for tiling

[twiggs396]

Hi all, my bathroom has just been fully plastered.
The plasterer told me to mist coat the areas that are to be painted and use a dilute PVA mix to seal the areas that are to be tiled. I have seen on here people say is a big NO!

But in the wet area within the shower/ bath I will be tanking over the PVA. Would this be ok to continue like this. As the other tiles will never really come into contact with water.

Thanks
Jon