It's only dangerous if you do something stupid like try to use it as a cruise control. The way the original setup was done was with a one-way connection that allowed the driver to set up a faster idle speed but still allowed normal use of the gas pedal. The throttle knob was usually used to increase engine speed for PTO operation, or possibly to set the vehicle speed in first gear to crawl along out in a hayfield, etc. while bales were being loaded. The hay crew my son worked with had a cable-operated throttle on a Dodge flatbed for just that purpose.
Jerry

"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln
Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt!
There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway
Love your enemies and drive 'em nuts!