Mr. grimmace may be thinking of the "old" doc. 550 ?
Just to bring Mr. grimmace and others up to speed here ;
The AMA states in Document #550 , Paragraph 3 "operations - requirements - limitations" Subtitle e)
"During an FPV flight , the FPV spotter must be prepared to acquire the transmitter/control from the FPV pilot and assume VLOS control of the model aircraft at any time safe operation of the flight is in question"
In other words , the AMA has the Pilot and spotter playing "pass the transmitter" during the very moment the flight is at it's most need of corrective inputs . Ever seen the results of a Newb tryin to hand off the TX to the instructor when a normal non FPV training flight goes awry ?
To the AMA's credit , Paragraph 3 section a) DOES mandate "FPV novice pilots undergoing training at low altitude must use a buddy box system with an FPV spotter , or must go to a safer altitude if no buddy box system is used "
So even in the case of a newb FPV pilot , if you've got altitude on your side , to hell with the buddy box alltogether .
Try this , take a model airplane , FPV equipped or not , to a "safer altitude" and aim it straight at the ground . Now hand off the TX to the person next to you , and see if he can save the model .
Wanna bet the ground wins the battle of the seconds past as control is re established ?????