This 'protection' becomes necessary if one mounts arbor/wheel to the left spindle. Me thinks they realized it is possible, therefore, someone WILL do it.
I understand your concern about 'standing in the line of fire'. They DO occasionally 'fly apart'. I am concerned by some recent grinder 'designs' that seem to be only able to deflect 'sparks/grinder waste' and are totally inadequate if wheel 'flies apart'.
Don't know if the washers/collars are undercut, but if NOT I would NOT use as a Saw arbor. Since it is 'INTENDED" to be used as a grinding wheel arbor. the undercutting would be less critical because of 'paper' washers that are typically attached to grinding wheels, but undercutting would still be appropriate with grinding wheels.
