Nope. Just kill them the first time....
If the original law called for the death penalty, I would think that they had been given fair warning. I can’t say that now. Put it on the record and next time they have no excuses.
Let the first timers go home. Let those caught two or more times rot in an outdoor enclosure. Give them a one year sentence for each time they’ve been caught coming in over once.
To just lop their heads off now, would cause us to look maniacal.