In my opinion, this is a very unprofessional decision by Guidry. If JL had already signed a contract for next year or had a year left on his current contract then he can resign at anytime without penalty as long as it's not within 45 days of the start of school. It's professional courtesy to inform your supt if you are applying for another job but it's not mandatory. If JL gave Guidry this courtesy then in my opinion, Guidry should have give JL the same professional courtesy of not squeezing him to resign before accepting a job. If Guidry wants to play the game that way, he can expect some surprise resignations in the future.
So, if Guidry ever decides to leave SH, should SH treat him like he did JL?