I noticed that when Joe Biden was signing the stack of executive orders yesterday he used a new pen for each one which was than placed with the executive order. What is the reason for this? The only thing I can think of is that the pen is stored separately and, in case of doubt about the authenticity of the order, the ink in the pen and on the order can be matched.
buenchico, that reminded me of when I went into a shop that sold many items. I asked the assistant if she kept stationery. She grinned and said "only when I'm standing still".
in olden days people who sold paper and writing materials tended to set up shop near universities or churches, where all their customers were, rather than touring the town fairs as other pedlars did. Hence stationary and stationery, the same word.
I think the first answer was correct. The pen that signed the declaration of 'blah blah blah' is kept, and either sold or given to some crony or other with a certificate saying this was the pen that signed the declaration of 'blah blah blah'. Good souvenirs. May well turn up on antiques road trip at some point.