Hmm. Sounds like doctoring the lucozade
or a guilt trip is the only way to go - maybe a note stuck on your supplies to the effect of 'this may be just a stolen snack to you, but if I go hypo & have no food left to treat it I could end up with brain damage or dying...in which case my family will sue YOU. Ps, Smile, you're on hidden camera As*****!"
Or something similar??
Or something similar??