What happens if somebody does eat it?? I mean it's food safe cause u can put it on a cake right?? I'm just thinking how to explain to a customer why there is something non-edible on a cake

I always explain it as...while technically there are edible....that doesnt mean that it would taste good..and that always seems to work...

I really have no input but I actually prefer not to use non edible materials on my cake other than the support and structure. It's just me. =]

I don't say anything if there's just a spot here or there of highlighter dust. Otherwise, I say something similar to padawn71's instruction, adding that it's like eating crayons... it won't kill you, but you wouldn't want to scarf down the whole box.

If I've covered a large area with highlighter dust, I recommend to the customer that they don't serve that piece to a small child, or just scrape that part off altogether. That's pretty rare, tho.

Totally agree w/DianeLM.
It *IS* a heavy metal. Any ingested will remain in the body forever! It can build up in time and cause health problems. However sooooooo little is consumed one would have to be *highly* sensitive to heavy metals &/or have lots of health problems to be effected.