There were many times that the BOC ordered large number of notes printed up, only to be mostly unissued and destroyed. I.E. the 1954 Lawson/Bauey $50 notes, they printed a large amount, only released a small amount into circulation, then destroyed the rest because they released the 1975 Mountie $50s. Why not just release both the 1954 $50s and the new 50s? At the time during the 1970s, both the 1954 and multicolored series were in circulation. So instead of just burning all those newly printed 1954 stock, just release them into circulation until they wear out. Also I don't think counterfeiting was a big a problem as today, so they still had good security features. Also the 1954 $1000 T/C signatures, as somebody pointed out, they printed 240,000 notes, released a few, then trashed the rest to release the bird series $1000s. Again, why not just release the two side by side. Why would they print so many T/C 1954 $1000s if they knew the bird series would be out soon?