According to the Tile Usage Policy (Tile Usage Policy) no-cache headers are not allowed, but during testing we saw that a client could direct their browser to turn on no-cache themselves. Should we try to stop that somehow with our web application? Does this run the risk of the application being blacklisted? The HTTP User-Agent fields and HTTP Referer fields are both being used in the header.
If you’re making a web page you are not responsible for extensions or configuration changes that users make to their browser of their own accord. Those changes might result in their browser not loading tiles, but that’s the user’s problem.
A browser sending no-cache headers in response to a shift-reload is fine.
As a practical matter, we’re currently dropping all no-cache headers from public sites so adding them won’t have any practical effect either way.