Bike Anti-Porn - When Things Go Wrong

Yeah now that you mention it, I bought a stem today and to my surprise there was a sticker on it that said you must always install a 5mm spacer under the stem, and if you have a carbon steerer you should also have a 5mm spacer on top. I don't believe it because I've never heard it before.

that sound pretty normal to me, especially regarding the carbon steerer.