Progress report for us: Dee has a 3-week AAT assignment at the high school where we did our Observations; we have done two of the three visits and will do the third next Tuesday.
The students -- there are about 10-12 of them in the group, with 3 or 4 AAT teams -- are very taken with Dee and have taken on the task of teaching her 'leave it.' So we are getting in a lot of practice, and it's going well! The students each do their own 'leave it' drill with her; some like to line up treats in a row and then release her to eat her way down the line of treats, while others like to put just one treat really close to her paw, which makes her almost cross her eyes.
But she's now recognizing the command 'leave it' and does not require forcible restraint when the food is there. This is not to say I would ever trust her without a leash on her when food is present.