I work as a data analyst and one of the first things i noticed was how people would game the systems to give the expected data result, rather than to show the reality.

Recording time via an app? More often than not its based on a phones internal clock rather than GPS so can be manipulated simply by changing the time on the phone...

Expected to answer x calls an hour? Just lift and replace the handset each time the phone rings... Counts as an answered call on systems, but benefits no-one.

Monitoring seatbelts? Drivers will use the passenger seatbelt buckle in the driver slot or buy one of these.

Monitoring breaks? Drivers will piss in bottles and talk about it all over social media.

Amazon need to be careful that fear of discipline does not surpass the need for good data, otherwise the objective data becomes 'manipulated' for want of a better expression.