Looking into this today things have been complicated by bug 1570072 which allows staff or patrons to update existing holds when these values change. for <3.5 it can be as simple as changing the condition in Suzanne's branch from "if (!notify)" to "if (!notify && !(notify === ''))" to combine her and Jeff's approaches, but for 3.5+ it needs to do a little more than just nope out. I'll see if I can throw some tuits at it.
Looking into this today things have been complicated by bug 1570072 which allows staff or patrons to update existing holds when these values change. for <3.5 it can be as simple as changing the condition in Suzanne's branch from "if (!notify)" to "if (!notify && !(notify === ''))" to combine her and Jeff's approaches, but for 3.5+ it needs to do a little more than just nope out. I'll see if I can throw some tuits at it.