The only way you can lose money with these methods (if applied correctly) is on a false breakout.
In other words if you get triggered into a trade and then it retraces and stops you out.
This scenario is highly unlikely if:
The flag pattern you chose to trade really looks like a flag: long surging bars in the flagpole and consolidating bars in the flag.
The OVI is persistent and supports the trade.
The volume pattern shows a sharp increase during the flagpole formation and a consolidation (gentle decrease) in the flag itself. Volume patterns that we like are the same for bull and bear flags.
You have set your order to trigger at the correct breakout price: slightly above the flagpole tip for bull flags and slightly below the flagpole tip for bear flags.
You have set your stop at the correct price: slightly below the flag low for bull flags and slightly above the flag high for bear flags.
You have correctly set your first profit target (roughly 1/3rd the flagpole length away from your breakout).
You are trading with the trend of the stock i.e. a bull-flags for an upward trending stock and a bear flags for downward trending stocks.
You are trading with the trend of the broader markets, or sector.
There is no news out immediately before you trade because then the move has already happened.
There is no news coming in the immediate future, either on the stock itself or from the US government.
If there is news coming in a few weeks you must be able to exit the trade beforehand, so leave yourself enough time for the trade to materialise before a news announcement.
You should be able to answer every one of these with a yes.
With all these elements in place the likelihood of false breakouts are small.
Your trade selection and management are key.