I've tried it, and it's a pain even with dedicated keys. This is one point of Raskin's design where the rationale is sound, but the solution he found was sub-o

I've tried it, and it's a pain even with dedicated keys. This is one point of Raskin's design where the rationale is sound, but the solution he found was sub-optimal. Instead of a "pure" quasimode, modern interfaces do incremental searching following the search box style introduced by Firefox, with a persistent dedicated and non-obtrusive search field. I find that this is a superior interaction, and it still can be considered non-modal. The style has spread to notifications too, with browsers showing small rectangles above and below the window instead of an obtrusive modal alert dialog.