I keep hearing that about tinfoil slivers in cake slices, and quite honestly, I cannot figure out how this happens or if it does, why it isn't noticable. Is it just me or wouldn't the fact a piece of foil was stuck to the bottom of the cake be fairly obvious? There will be a piece of foil missing from the cake board, for one thing. Don't most folks put the slice of cake on its side or do they stand it upright like you would for a square of sheet cake? I would think people are using heavy duty foil and that stuff is hard to get slivers of foil from.
I actually have seen posts saying aluminim foil is not food safe. Now aluminim foil has been used for many years in food production. Other than some studies showing a high concentration of aluminum in Alzeimer's patients, I cannot image anyone cutting their throat on a piece of aluminum foil.
To me the drawback on using it is people do not apply it correctly and it always seem to look really crinkly and wrinkled, not smooth. That drives me nuts when I see a gorgeous cake on a wrinkled up tinfoil covered board. Haha, I got myself into trouble on the Wilton site one time about that. There was a new decorator who turned out some of the nicest and most perfect cakes I had ever seen and she asked for critiques. Basically I told her that she could charge hundreds and even thousands of dollars for her cakes but that the tinfoil covered boards detracted from her amazing work. Well she was offended and none of the many compliments I made mattered.
So if you are going to use tinfoil, roll out a piece and cut it very carefully so as not to get any wrinkles in it, it can be done. Then lay the foil on a very flat and smooth surface, dull side up. Put your board on top of it and very carefully smooth it to the board and tape or glue. Cut the tinfoil in strips close to the edge of the board, like a fringe really. Then you avoid a lot of bulk when you smooth it to the surface.
Hugs Squirrely Cakes