Currently links to published spreadsheets or reports are "hard coded", i.e. can't be changed. So if someone either from our or from customer's side is leaving the company, they still have an access to potentially confidential information. This "feature" makes use of Smartsheet in the enterprise area very questionable and risky.
The only workaround so far is to copy the spreadsheet, delete the original and publish the new one. At least it would kill all change history for the spreadsheet which is a major disadvantage.