What you're talking about would typically be considered illegal in the United States under FDCPA (Fair Debt Collection Practices Act) so I'd imagine it would have to be a private message.

(For more information about debt collection, I'd recommend https://www.consumerfinance.gov/consumer-tools/debt-collecti... )

Even if you improve collection practices a tenth of one percent, however, you're still talking big money so I see the appeal of the market size and any potential improvement.