Here goes the racist answer,
Typically gringo neighborhoods don't have people familiar with the more tropical fruit trees...and seems like u can get away with advertising most tropical fruits, and not being able to give them away in such areas, so u may be much safer....Your chances may be good because even the fauna in Canada wouldn't know what to do with a mango!
But in areas with large populations of those who grew up around such fruits ( like Asian, Latin, Indian, and many more) you have a higher chance of having someone pass by the tree who associates good times, good eats and value with your plant.
So you must be unlucky enough to have someone who recognizes the fruit, and who is willing to steal a large plant!
Weigh your options...it could be worth it to grow in your front yard! especially if well lighted by the sun, and in a protected location from wind!
Good luck!