I doubt it's true. And if it is it isn't this particular picture. Cabbies in UAE have two things deterring this from happening.

1. Two cabbies share the same car. They do 12 hour shifts (from 4am to 4pm and 4pm to 4am). The cut they make is about 10% from total fares. And every cabbie I've ever talked to says they try to get about 200-300 dirhams a day. A minimum fare for a trip is 12 dirhams. They need to do quiiite a few trips to make their targets.
2. Cabbies in Dubai all have uniforms and it sure as hell isn't a bright pink shirt and jeans. Typically its a white/cream shirt with the taxi company logo (quite a few taxi companies here.) and brown pants.
3. Uber drivers seem to wear suits most of the time and Careem (local Uber) drivers have a Careem tshirt/shirt.
   

Given this it's unlikely they just hopped out the cab, said fuck it to the cabbies targets and spent a day in an amusement park.

Source: Lived in Dubai for 24 years now.