The "shaka", which is what it's called, began with a member of the church (Hamana Khalili) in Laie who had lost his three fingers in a sugar mill accident. Prior to the establishment of the Polynesian Cultural Center, members regularly put on a fundraising event by performing a Hukilau (Hawaiian type of net fishing) on the beach, followed by a cookout. The brother with the missing fingers stood on the road waving to tourists to attract them to the event. It was picked up by tourists and popularized by surfers.

Having served with the PCC I have spoken with numerous members who were part of these events and verified this provenance.

So, it is not some fabricated thing or unrelated to the Church or BYU with its dominantly Polynesian coaching staff and large number of Polynesian players. It is no less appropriate than doing the haka before games.