I don't want to call myself an "expert." Let's just say I have
a lot of experience. (Obtained my first Ruth autograph in 1965, my first Gehrig in '66. Here they are--and they are both good.

)
Was I fooled by that '27 ball? Yes I was. So was Jimmy Spence. So were two top collectors and a dealer who wanted to buy it from me.
Everyone makes mistakes.
But if one sells his "expertise," one should be held accountable.