Passengers using several apps for one fare is rare. There were always a few that'd ring several firms for a cab but very few and even less on apps. I suppose with apps they know that everything they do is tracked and logged so they figure they'll be banned if they abuse them. What will happen with competition is that they'll order from the firm with the shortest run in time displayed and eliminate firms that let them down. As time progresses they'll get pissed off with one and switch to another, get pissed off with that and switch to another, get pissed off with that and switch back to the first, etc, etc. Having two firms in Sword worked well over the years. Both pissed off clients every weekend so the clients switched back and forth from week to week.
The bigger question is whether drivers will use several apps. The likelihood is that they will use one or two at a time based on bonuses on offer or how much work is available. Running several apps means having several apps constantly drawing on limited resources of smartphones and mobile internet. Even with 4G four apps running simultaneously will slow each others communications. Slower communication will, in turn, result in less viable job offers.
Which one are you currently endorsing, erm? I'm guessing that you'll be in for a serious kick up the arse from Bill Cullen if Whistle or Flag (or any other app) impacts on mytaxi's virtual monopoly to any great extent.
Anywaysanall, back to the Xmas bonus. I didn't work Friday and managed the ton on Saturday, worked from 18:08 to 04:26. Having destinations on a lot more job offers helps.