The lowest fares on YVR-YYJ used to only be offered on YVR-YYJ mid-mornings and on YYJ-YVR late evenings. It looks like they may have relaxed this a bit.
FYI...the Tsawwassen-Swartz Bay ferry Spirit of Vancouver Island was running almost 3 hours behind schedule today and people are apparently sleeping overnight in the vehicles as well at the terminals.