Security tapes ran at a slower speed to allow for more time per tape, and required special VCRs that could play at that speed.
If you were looking for oddities, check these out:
https://www.youtube.com/watch?v=1Dan_bJZzwQ
https://www.youtube.com/watch?v=pDGhFFRkJi8
Found these in a box of Betamax tapes I got from an Ebay seller, dating from the 70s.