You can spot the 'spoilers' by checking their financial information. An airline that has been consistently in profit and is posting low ticket prices is probably looking for market share on that route and is subsidising losses on that route from others it is running. I see this as ligitimate.
The spoilers are those that have never made a profit and in particular have very low, almost zero ticket sales.
They also usually have 3 beech or j31 indicating they have bought from a "sister" airline run by the same person.
Where these circumstances are identified the airlines should be removed as there is no ligitimate reason for an airline to behave like that.
These two airlines appeared on the Manchester - London Heathrow with $0 prices. Looking at the airlines they have never made a profit and are ghosts designed to free up slots! What can be done about this?