My theory on this is that the pin is only there for initial alignment of the parts. When you torque the cam bolt the press from the bolt is actually what should be holding everything together. So if the pin is a slip fit, and not sloppy, there should be no problem. The washer under the bolt should apply the force to hold it all in position.
I've read of situations where the pin has slipped back and no longer engages the fuel pump eccentric, and then the eccentric starts rotating. To me, that indicates inadequate torque on the cam bolt. It should be torqued to 45 ft-lbs when you assemble it.
Same goes for the front crank bolt, by the way. The press from that bolt is what should be holding the lower timing gear in position on the crank (through the washer, harmonic balancer, crank sleeve, and oil deflector), not the keyway. That bolt is supposed to be torqued to 150 ft-lbs, and for good reason.
JMO - flame away LOL!