Ok i know wild yeast is everywhere. When you brew and transfer outside. To the fermentor. But is this a big issue.
It’s not too big of an issue. First the hops help fend off wild yeast. In addition, you’re pitching a big healthy population of yeast that will outcompete wild yeast.
If you don’t follow the above you could have problems. In Belgium they use shallow, wide square fermenters called coolships. This allows the wort to cool and collect the wild yeast for their sours.