I just feel that fake casting just ain't worth it. You never know if the opponent is bad enough to not use his interrupt at all, which leads to unnecessary fake casts. Also, with spells, such counterspell and glyphed strangulate, you just end up having to suffer 4sec (5 with strangulate) silence instead of 7 (YAY!). I mean usually you will end up in better situation if u manage to pull 1flash heal off and then suffering the 7sec silence, rather than not getting single heal and suffering 4-5sec anyways