We had the same issue with this club and the same player a few clashes ago. The player and 2 others from that club scored over 500 points each but their scores for each round would never have accumulated the scores they had.
I've noticed that they start off very slowly (near the bottom) of every clash but fly up the leaderboard all of a sudden.
We have very good Champion tier players in our club and they've also agreed that those scores are not achievable.
I reported it to WGT, along with screen shots of their accumulate scores and their actual scores and got a reply that didn't even relate to my question.
They are definitely doing something to enhance their scores!