I spent some time learning the markets recently and this is kind of my interpretation.
"No way" you can lose buying at markets... well except if you go all in like these p1-5(5 persons).
bid/ask 100/101 p1 buys at 101
bid/ask 99/100 p2 buys at 100
bid/ask 98/99 p3 sells at 98
bid/ask 99.5/99.6 p4 buys at 99.6
bid/ask 99.25/99.26 p5 ...
Even if all of these people bought lower ("adding to loser") it doesn't really help, the clever algo they use always find a price where everyone who holds winds up holding a losing position. Even if you bought from some clueless dude, if the clueless dude decide to exit the loser, their position probably ends up with the clever algo guys and soon your profit goes away. Trend is a bunch of people holding losers thinking it can't go lower/higher.
At this point the exchange says they add more decimals (0.01->0.001). Then next thing they add weekly, daily, hourly, minute option expiries. (the option hedging is what causes people to lose money if they hold over night and the more frequently it's done the less likely profits are - once people figured this out and started to sell options, some brokers added all sort of obstacles, fees and arbitrary margin calculations to make sure no one tries to sell options)
That's just 2 tricks, they always invent some new trick if people find a way to quick profits to make them lose money faster should they catch up to their old tricks.
Latest trick could be this one "Nasdaq will introduce a patent pending Retail Order process"... The only people making consistent money are the financial industry firms, brokers/market makers by nickel and diming everyone in hundreds of ways. So IMO unless one wants to be one of those, participating seems a bit pointless.
The typical way around this is to set up a 'bucket shop' and then tell customers they cannot use bucket shop for hedging. (all while the bucket shop hedges so their customers end up losing)
Now there may be ways to actually make money there if one is able to determine what something is really worth and have patience to wait for there to be losers to be found to the wrong side of the accumulation process. But that kind of process can take months, years and no telling how low the price can go. What is gold really worth.. .Yeah hmm. My guesstimate is that gold will go so low that many mining companies get bought up by some bigger interests and enough speculators give up on it.. etc