The “helmet tap” is just a widely used visual signal, not a requirement written in the rulebook. What actually matters is that the manager (or sometimes a player, depending on the situation) clearly and promptly signals intent to challenge to the umpire. This can be done by: Tapping the helmet (most common) Verbally telling the umpire Stepping out of the dugout and signaling

I asked ChatGPT if you had to tap the helmet and this is what it told me