Well THAT was certainly a leap from the previous discussion. Do you NOT think it's fair to verify from scripture what someone teaches you or tells you?? Or to encourage others to do the same? There are numerous examples in scripture of God's people verifying from scripture what Godly practices are.
It's not about "fair"....it's about "Truth". I think you learn how to identify falsehood and false teaching by already knowing and understanding the word of God....and study of.
Those who are taught how to identify counterfeit money are NOT taught what the phony stuff is....they are taught inch by inch, in every minute detail, what 'true' bills look like and are. Thus they can identify the false bills because they are well familiar with what is “real” (truth)