Of course those numbers are possible. What is not possible is to have 100% consistency. 100% consistency for 3 weeks does not mean 100% consistent.
My guess it's a futures scalper, using $500 or less intra day margin. Nothing is held overnight. Just do the math.
8 S&P mini contracts = $4000 needed to enter, per trade.
8 x 2 ticks x $12.50 a tick = $200
Commissions, let's say $4 RT per contract = 8 x 4 = $32
profit per trade net commission = $168
notes:
1) A 5K account could trade a MAXIMUM of 10 contracts at least 1 time using intra day margin of $500 per contract. Intra day margin requirements are negotiable, so it is possible an experienced scalper would have a lesser intra day per contract requirement.
2) Scalpers negotiate significantly reduced commissions ($4 rt would be extremely high) due to very high (daily) volume. It would not be surprising for the scalper to have exchange membership.
3) Scalpers enter (and exit) dozens if not hundreds of trades per day. In the above example, 12 successful trades would produce $2016 net commission. The question is how many licks does it take to get to the center of a tootsie pop. When you can answer that for yourself, you will know that you know how to play the game.