Ever heard of Zapier 'owning' your custom fields?

Was chatting with someone in the CSM department and they sad someone who maxxed out their custom fields. I gave some suggestions on ways they could work on backing out and recapturing some custom fields. Their response was this:

Thanks Jeff, I think where they were seeing issues is backing out of some of their custom fields since zapier owns the ID creted when the customer field is created, when they delete it the ID remains and in essence breaks. At least that is how support went over it with them. so they were told they cant delete any cutom fields due to this. any thoughts there?

Anyone ever heard of such a thing? Sounds completely ridiculous to me, but …???