I don't see anything about it being dewaxed?  The Zinsser shellac in a can is not dewaxed and I assume the rattle can version is the same stuff?  Their Seal Coat sanding sealer is dewaxed shellac but since their rattle can shellac does not mentioned being dewaxed, I would assume it is not.  It might not hurt to wipe down the surface of the shellac after it dries with some mineral spirits to remove any wax that may be on the surface.  Just a theory but the MS should not hurt the shellac.  It would be nice if they would sell a rattle can version of the Seal Coat. 

BTW, I've read that one way to dewax or at least remove some of the wax of the standard stuff is to put it in the freezer.  The wax will congeal and when you pour it through a paint strainer, much, if not most, of the wax will be captured by the strainer.  IIRC, if you repeat the process a couple of times (let it warm up and refreeze), you will remove even more of the wax.  Of course, it is simpler to buy just dewaxed shellac flakes and mix up your own but this might do in a pinch.

--Nathan, TX. Hire the lazy man. He may not do as much work but that's because he will find a better way.