These are actually not very large wins for 15 days of play, which suggests to me this casino has a fairly small player base. It is possible as Zap points out that they might have just one person who plays high stakes.
If it were deliberatly fabricated to entice new players, then you would have thought the casino would try and make some names up with bogus win amounts.
Probably best to keep an eye on the forthcoming winners, because this JLT48 can not go on winning forever. Unless the casino has only 1 player!
Mike