I'm travelling from Toronto to India via Abu Dhabi with Etihad Airways. Do I have to get a visa to get out of the airport if I have to spend three days in Abu Dhabi?
You will receive a Visa on Arrival classed as a transit visa. As long as your passport is valid and you show proof of onward travel, you do not need to preorganise a visa.
"The transit visa is valid for 14 days, starting from your arrival in the UAE. If you are transiting on the third destination on your trip itinerary, you will need to have proof of a confirmed onward flight (i.e. an air ticket). Your passport must be valid for a minimum of 6 months."
Taken directly from this site: http://www.abudhabiairport.ae/english/airport-information/transit-information/more-than-4-hours.aspx