[pajtai]

I would modify the script to display a notice:

"Thank you for using SortTable from https://www.kryogenix.org/code/browser/sorttable/. If you, the site owner, would like to use SortTable without this notice, please download the script from [here](URL link) and add it to your server."

If you want to get fancy you can serve the modified script only if it's being hot linked and the original script if it's being used on www.kryogenix.org - or another website that has permission to use the script.

[noway421]

I think this is a brilliant solution - you can also make it the second row in the table that's being sorted (right after the table header). That way there's no breakage and it's a good enough deterrent.

I would go on further and make a link to a Stripe Checkout page that allows you to purchase a license subscription to remove the notice.