Before rushing to the idea that a local event invalidates a destination, one must ask what protects our planning.
The exit condition is often less absolute than we imagine, especially if we have some flexibility.
An event, even major, is not always an universal blocker; its impact often depends on our own personal constraints.
For example, the Dour Festival makes the region unlivable for tranquility, but if we just shift the visit by a few days, the pressure on accommodations disappears.
There is often a fail-safe if we are willing to adapt or seek alternatives nearby.