Word. I find doing this off low level shit like 5k xx rashou or 5k xx rensen works well for this kind of guessing game, to be worth noting, too.
5k xx rashousen hits a lot of people just based on the fact that it's unexpected early in a block string, especially when you're right in their face, doing a move that's almost 30f start up off a lvl2 move.. nobody expects you to be that ballsy. After seeing it the first time, you get to play the same game you described.
Only problem is that IB'ing 5k can let them punish rensen or rashou with a fast enough move.. but with decent spacing (~max range to gatling cl.5S range) can make them think twice about IB > buttons. Unless they've got the eye of tiger and can just see rensen/rashou start up and react fast enough punish it off IB.
edit: Off 5k xx rensen, you'll likely want to FRC every time, as point blank rensen (I believe) puts you at a disadvantage on block.