I think most users of OA (which is actually approved as an organic treatment for trickling !)
Apibioxal is the only VMD approved (and legal) OA treatment that I know of for both trickling and vaping.
Worth noting Oxalic acid is what is know as an organic acid, not a soil association certificated organic produce
I was pretty sure I saw somewhere that OA applied by tricking in sugar solution was an approved treatment but ...memory does sometimes play tricks so I'll have to look further- you may well be right - in which case I reckon at least half of the hobby beekeepers I know have been applying an illegal treatment for years (not that I think opening the hive in December or January to pour a solution of OA In syrup on them is a good idea) - although it does work apparently - I've never done it.
I did not mean organic in the soil association sense...I meant it as organic in the sense that those averse to applying chemical treatments might find it more acceptable ... perhaps we should be petitioning the new environment minister for a dispensation for generic OA to be allowed by the VMD ?