How programmers comment their code

Have reviewed 16 year old code for a very well known company in the last week with this exact comment peppered throughout, alongside delightfully helpful comments like:

// do not delete or change this it just works

// TODO temporary fix added 12/09/11 to fix incident must be removed ASAP

// CAUTION this returns false here instead of true like it normally does, not sure why

// if true then matched to valid account not is true