I read something a couple of years ago about the phenomenon of expats fleeing Dubai after the economic downturn because of the Emirates' harsh treatment of debtors (no bankruptcy, pay up or be jailed). Supposedly, it was common for people to just abandon their cars at the airport and high tail it out of town, never to return. I just found a delightful article highlighting the phenomenon of swanky luxury cars being abandoned at the airport or on the streets. I suspect that this is the main justification for the imposition of an exit visa. But of course the upshot is probably that British financiers end up fleeing their debts anyway, while poor Bangladeshis suffer indentured servitude.
You're a bit muddled up here. Tinpots dictatorships of various flavours have required exit visas for years, sometimes even for their own citizens, but Dubai/the UAE does not and has not.
http://www.messynessychic.com/2013/05/21/so-in-dubai-the-amo...