may be shipping a piece that will require assembly as some parts are too long to ship economically
have seen very very thin plastic sheets used for labeling parts where they adhere only thru static forces or van der waals
but mostly that was for flat pieces
tape is too messy and post it notes fall off
this is not something i have had to do or thought much about
looking for cheap and reliable solutions that would mean they stay on in shipping and unpacking and can be easily removed once assembled
i imagine ikea probably has a large team that does nothing but figure out how to make fool proof assembly instructions but even then there are assemblers that will do it for you