Usually, the UAE Government deports individuals from the country primarily because their activities may be a threat to society which includes reasons such as public security, public health, public interest or public morals.
According to Article 15 (1) of the UAE Immigration Law, it reads as follows: “The Federal Attorney General or his authorised representative and the President or whomever he delegates may order the deportation of the alien even if he has a visa or residence permit, if such deportation is required by the public interest, public security, public morals, or public health, or if he has no apparent means of living.”
Any person may also be deported pursuant to an order made by a court in the United Arab Emirates with jurisdiction over the case or on the direction of the Federal Authority for Identity and Citizenship, Customs and Port Security. If the President of the State grants permission, a person who has been expelled from the UAE may return. The UAE Immigration Law, in Article 18(1), stipulates that "The Alien who has previously been deported may not return to the State without the permission of the President."
So, in hindsight, there are various reasons to which a person may be deported from the UAE. But, he or she can re-enter the country only when the President of the State permits.