Depending on the complexity of a strategy, a lot of strategies can be reverse engineer if an experience trader get enough samples of the strategy. As mentioned above by @southall, nobody wants more competition on entry fills and more slippage on exits. However, most people wouldn’t try to reverse engineer what u are doing unless they know that u are a proven profitable trader because with the time spent to try and reverse engineer someone else’s strategy they are better off developing their own strategy.
You could make a mint by reverse engineering all my trades and then taking the opposite side, which is why I would be too embarrassed to post my trades. My "Whippy-Saw" trading strategy would be totally exposed. But these postings confirm my suspicions about those who concern themselves about this.
Is Reverse Engineering Real? ----> Is Reverse Engineering Useful? YES! reverse engineering your own charts, not other people's (useful / useless ) charts
A counterpoint is the journal some years back on "ES Trend Following", where the entry was off an hourly consolidation pattern (long, long horizontal box). He did remarkably well until he didn't. The pattern disappeared once his performance got noticed. Just random? You decide, but this forum is a pretty good contrary indicator at times, for anyone on the inside...
He was joking --- fit some trades on a chart and said if you can figure out how to duplicate this through "reverse engineering" you can make a million.