Most of the user that participating in the tournament do a calculated gambling therefore they weigh in already the potential profit and loss if they compete on this kind of tournament that push user to wager huge volume to win that prize.
Assuming that there will be a toe to toe battle on the top 3 spot, I think all of them will be spending more than the rewards allocated on the tournament just to protect their rewards that allocated already as their cashback.
They surely read the tournament rules, watch it for a while, do their maths in order to consider risk and chance to win in a tournament. There is no clock work for them and sudden changes in a tournament and leaderboard can appear to make all maths are inaccurate and no longer helpful. In tournaments, gamblers with bigger capital will have more options and they have higher chance of winning and taking reward.
With good approach, and support from big capital, they can have more comfortable options and most of time can easily beat small gamblers who join in a same tournament.