When will Gym Leaders visit your Avenue?

Question

BW2 Btw, I'm just curious since they give a bunch of Exp. for the Avenue

Answer 1

After the player has entered the Hall of Fame, Gym Leaders will occasionally arrive among these, as a bonus.

When you become the champion it seems. Based on the wordings, I would guess that this is still rng related and that upon becoming a champion, there would instantly be a gym leader in the place

Source

Comments

If it's still rng related, there are odds for when they can come or not.

And I can say from experience that gym leaders don't just appear if you have entered the Hall of Fame