Well, I'm one of those players but obviously no cheating is involved.
Simply is the same concept of an ebay auction.
You place your bid in the last few seconds, so other people don't have time to react and can't overbid you.
In smutstone, I collect money and when I think I'm ready, I decide a day to compete in tournament and get 1st prize.
During that day, I simply play and gain a medium amount of points (around 600). Then, about 10/15 minutes before the end of the day, I level up / open chest / evolve my cards until I reach the 1st prize spot. The other players have no time to react and I never failed in getting the prize in that way.
Now I'm in Tournament Tier2 with 2 copies of the prize cards.
As for the fact that is impossibly for f2p players to get far, I totally disagree.
I spent 50€ to get Casanova Pack 3 and I regret the choice because that pack wasn't useful at all!
The only card I'm still using is the healer but she will be replaced soon when I'll get to rank3 Tournament. Is just a matter of time.
If you want to get far in this game just follow these steps :
1) Find the level that gives you the most money, without the risk to die and farm that level. Also farm the materials required to level up cards.
It should take about a week to have enough resources to pay a good tournament, but it depends... one week I was able to rank 1st in 3 different tournaments.
2) Never level up / evolve your cards, unless in the days you want to compete for 1st prize!
3) Don't compete in tournament prizes unless is the day you decide you will get 1st prize, because other prizes suck and they are just not worth it.
4) The day you decide to compete, just farm as usual. About 30 minutes before the end of the day, check the tournament... if the first 3 players are in a fair point range (usually about 1100-1300) then you can go for it! Open your free chests, level up and evolve your cards, beat some new level and you will be able to reach the first prize. When you will get used to it, you can login later and give your opponents even less time to react. I'm now able to do it just in about 10 minutes!
5) Now you have your 2 new cards, which are 2 of the most powerfull out there. Put them in your deck, farm for another week or until you have enough money/items and repeat the process.
It works... trust me!