Describe the solution you'd like
An indicator that displays to players that they will be receiving reduced or no experience for breaking a block they placed.

Why is this feature needed
The player who is unaware of this anti-cheese feature will likely believe the lack of XP is a bug. This extra context helps to clarify the mechanics

Describe alternatives you've considered
none. This is needed for UX.

Additional context
The ideal implementation would be a small icon beside the crosshair of the letters "XP" covered by a red circle with line covering it. This should be small an unobstructive to the player experience.