Joseph, if someone received a benefit by falsely claiming to be a member of the clergy he can be prosecuted for fraud. If he received a tax break (and there are) he is guilty of tax evasion. The big question is who is clergy. An on-lie dictionary defines it as people (such as priests) who are the leaders of a religion and who perform religious services. It would be interesting to make a claim for a yoetzet halacha or a woman who leads of women’s Tehillim group.
As for male teachers, at one time many were misters. When this began not to sit well with parents they were given the title “rav u’manhig”. Even someone who has “Yoreh Yoreh” may not serve as a dayan unless he also has “Yadin Yadin” (see Sanhedrin 5a that there was also a semicha for allowing bechorot).