"I have seen threadlock mentioned in the cycleserve manual, presumably to prevent the bolt working loose in service, think about it, if the bolt came loose, what is holding your fork leg together, frankly, nothing."
Is this correct?.... is it not a fail-safe design, it the bolt cannot unwind appreciably due axle clamped over it?
Upto this point had always figured the seal was the job of the (serviceable) copper washer. But agree, if Soichiro Honda says 'use it'....!