Agree with wao
Ground gives taxi clearance from point A to the active R/W holding bay when departing the airport.
If Grd issued a taxi clearance included crossing a R/W on your way to the active R/W holding bay, then look carefully and cross it. If Grd didn't clear crossing R/W on way to the active....Don't cross it. If you don't know what ground said about crossing R/W STOP and ASK.
As wao said, stay with tower during rollout UNTIL ATC says exit X taxiway, and then when clear of the Active and on the taxiway, LISTEN before switching to Grd, 'cause Tower may be workin' both ATC and Grd at that particular moment and ask you to stay with him for taxi clearance. Otherwise he wil advise you to contact Ground @freq xxx.x
I see very little confusion with it in the Toronto area but that's MHO.