I am so with you all on this. I am a diabetic and persistently receive wine and chocolates from friends, and some family, who know this. At first I accepted so as not to offend, and re-gifted to my non-diabetic friends and family. But that just led them to believe I was OK with the presents.
Now, I receive, open straight away and share out amongst the non-diabetics in the company, and pointedly do not partake. When questioned I simply say "Oh sorry! I obviously haven't told you I'm diabetic. Can't have any of this, but you enjoy".
The thing is, they all know I have a passion for gardening and feeding the birds - a bag of bird seed, a pot plant, a gardening token, another bird feeder, some bulbs, packets of seeds....the list is endless and all highly acceptable.