Those found guilty of witchcraft in Salem were hanged. Several more died in prison.
http://www.salemwitchmuseum.com/education/
http://law2.umkc.edu/faculty/projects/ftrials/salem/sal_acct.htm
Being burned at the stake was a common punishment in Europe.
http://en.wikipedia.org/wiki/Witch_trials_in_the_Early_Modern_period
I would be very surprised if either form of punishment was implemented on OUAT.
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