One of my employees was contracting out his entire job. His performance was great and then fell off a cliff. Turns out he stopped paying the contractor and the contractor stopped doing his work for him. When he had to do it himself it was horrible.
Contractors are expected to be shorter term and change tasking if new opportunities arise, even for a short time.
If both parties enter into a deal then it's fine, if one is misrepresenting themselves it's not.
How quaint.
/s
When an employee does it without informing the employer or signing an agreement that holds the contractor to the same standards as the employee the chain of trust, transparency and accountability is broken.
Well, it's entrepreneurial, but he's almost certainly also violating all kinds of employment stipulations and policies he's formally agreed to (security, privacy, etc.)
It's in most standard employee contracts that employees won't disclose confidential information for reasons like this.