This is a fairly pointless comment, but since you asked, it's Section 2.1 of https://download.developer.apple.com/Documentation/License_A... which you may need to be a registered Apple Developer to view. So, a relevant quote:

"Apple grants you...license to....

(f) Allow Your Customers to use Your Internal Use Applications on Deployment Devices, but only (i) on Your physical premises and/or on Your Permitted Entity’s physical premises, or (ii) in other locations, provided all such use is under the direct supervision and physical control of Your Employees or Permitted Users (e.g., a sales presentation to a Customer);"