This still wasn't a good idea, but for a different reason - it's relying on the demo at https://igorescobar.github.io/jQuery-Mask-Plugin/ continuing to exist, and continuing to host the plugin at that same path.
Full disclosure, this mistake was not made by the campaign directly, but rather by Revv.co, who is the payments software provider (not processor, DJT is using Stripe).
This still wasn't a good idea, but for a different reason - it's relying on the demo at https://igorescobar.github.io/jQuery-Mask-Plugin/ continuing to exist, and continuing to host the plugin at that same path.