One big problem with comments is that many of the third=party add-ons are not comment-aware - presumably their authors were not comment-aware. In particular Tailor would never run with comments in the file. So vendors installing comments in cr2's would be well advised to place them only at the top of the file, where they can be easily found/erased if need be. IIRC // is a MetaCreations-added comment facility, # is a Alias Wavefront .obj standard, and can only appear at the start of a statement (i.e. not within multi-line one). And neither should be used as the very first line of the file.