National Forensic Academy teaches to dowse for the dead

Wikipedia sums it up nicely, with citations: -- The motion of such dowsing devices is generally attributed to the ideomotor phenomenon,[7][8][9] a psychological response where a subject makes motions unconsciously. Put simply, dowsing rods respond to the user's accidental or involuntary movements.

The scientific evidence is that dowsing is no more effective than random chance.[10][11] It is therefore regarded as a pseudoscience. -- https://en.m.wikipedia.org/wiki/Dowsing

For an entertaining time, check out the late James Randi and his debunking of dowsing

I remember an article in Analog, a very long time ago, that touted how dowsing was used to locate mines in Vietnam. John W. Campbell was into a bunch of silly things.

https://www.latimes.com/books/la-ca-jc-astounding-20181115-s...

There was a guy who made millions more recently selling fake bomb detectors that were used in places like Iraq:

https://www.bbc.com/news/uk-22380368

If it was not real, would they use it in life and death situations? Yes, yes they would.