Before rushing to the idea that local events are a major and always present component of destination validation, one must ask what could go wrong.
The exit condition is crucial, especially if your trip has a specific mandate, like visiting a historical site or family, where an event would be secondary.
The downside of a crowded or costly event does not question the destination itself, but rather the modalities and your flexibility to adapt.
For example, a beer festival in Munich will not influence my decision to hike in the Ardennes; the impact is conditional on priorities.
It is necessary to plan a fail-safe to handle surprises, rather than making these events the basic criterion.