Another good reason to start laundering before gifting...Frixion pens.
I mark the rows of blocks before putting them together and mark before quilting. The ink disappears with the iron, but will return if exposed to cold temps. I've been explaining this to recipients but taking care of that before gifting would be another good reason. Additionally, I've noticed the Frixion ink shows up "ghosted" under certain lighting, like under my Stella lights...so, all these, I think, are valid reasons for pre-washing.