Yeah, that is about exactly what I said to them. I am used to the New 3DS default controlsin particular, except with the far right trigger swapped to Jump and the far left one swapped to grab. After mentioning as politely as possibe, I almost got kicked out of the event for this, wich honestly in hindsight would have been preferable to having to play with the default controls AND not being able to play Greninja or even my secondaries Corrin and Robin in half of the set-ups.
That aside, mapping a trigger to jump is almost mandatory on Greninja. Many combos require fast jumps and immediate presses of the attack buttnos, and literally become impossible if you use XY to short-hop.