Guerrilla Grafting: Grafting Fruit-Bearing Branchesto Ornamental City Trees

My impression, although I don't live there, is that San Francisco has a fair number of homeless people. Surely they might be recruited to pick and dispose of ripe fruit before it becomes a hazard? In those locales that require refundable container deposits for the purchase of beverages, the homeless contribute a great deal to the fact that such refuse is absent from most streets. A piece of ripe fruit is surely worth more than 5¢.

These are interesting links, but they have to do with treating individual ornamental ash trees that are infested with a particular insect. Fruit can only be grafted onto the same species (or a very closely related one) so this has no particular relevance. Information about standard treatments for ornamental plums or crabapples would be relevant, though.