Mrslefty's post made me think of this... when you are moving or getting ready to go on vacation and you've got a book stuck in the "48-hour hold" FIFO line for one person after another who times out... what happens if/when you put your list on vacation hold?  Will it still be requested and will that book go on hold too?  Or is the only way to hold it to cancel it manually and then relist after your vacation/move is complete??

That book will not be on hold

If you have a request pending when you put your shelf on hold that request will not be put on hold.  Now once the request is accepted you can cancel it then and then repost once you take your shelf off hold.