Of course, it's a normal thing. Otherwise, you might end up with heroic paranoia.
The main point, however, is that such digging doesn't always give you an unconditional advantage. It might only work with the restriction of placing it in a Necropolis castle or a Tower. With three obelisks, digging from the 1st to the 3rd time is quite realistic.

Let's consider 2 cases:
1.
- The person cheats in general.
- The person cheats while digging for the Grail

Consequence: the more attention his game attracts, the more likely other suspicious moments will be found, which will help prove it.

- The person doesn't cheat in general.
- But cheats while digging for the Grail:

It's quite possible that his reputation will be more important than a dubious profit.

A real negative point: if the Grail factor starts to significantly affect the win rate. In this case, I'll admit that the idea didn't work out.

In general, I'm in favor of the experiment. We can always bring back the ban later.