you are correct that you are allowed to have a 2 day possesion limit on you HOWEVER you must be able to prove that you stayed on the river overnight. If you went back to a residence (even one not your own) then your first days possesion should have stayed there otherwise the CO/DFO officer is within his rights to ticket you. This is of course if you are stopped while on the flow or leaving the flow.
when im sockeye fishing i will camp out overnight alot of the time so i dont have to waste the second days gas of going back and forth. This is also a good way of having a little camping trip for the family