Hi Pat
Ok so when you say "Generally Known tactic"
you mean the Germans had some and the British knew about it. The mine the Germans were dropping had an impact fuse, see
http://www.navweaps.com/Weapons/WAMGER_Mines.htm
"Weight 1,213 lbs. (550 kg) with a charge of 661 lbs. (300 kg). Had a 22 second delay impact fuze which detonated the mine if it fell in shallow water or dry land."
ie for the mine to work on the land it needs an
impact fuse
If its any consolation the British did have some mines with impact fuses, the A Mark III see
http://www.navweaps.com/Weapons/WAMBR_Mines.htm
"Some were fitted for impact firing. Mark III*** was for dropping from Mosquitos at 260 knots from 300 feet (90 m) into inland waterways. Designed to be dropped from 4,000 lbs. (1,814 kg) bomb gear."
Note dropped from Mosquito not Swordfish.
No doubt they copied the German impact fuse.
You said
"it is possible that in some operation somewhere during the war that a Swordfish dropped a mine as a ground attack weapon"
It is clearly not possible unless the A Mark I mine has an impact fuse, which it has not.
In any case they are not heing used against tanks and infantry but against cities and in waterways do you really think they should be included in the game?
Best Regards Chuck.