I think the sticky note is great, but it is also a bit hard to see at times.  Placement is everything.  Maybe making it a funky color to stand out would be good?  OR...maybe an indicator on the dashboard of the client there could be an indicator that there is a note in that screen...much like when there is an error in the screen there is a red COME FIX ME indidator.  Just tossing out ideas here.  Easy of use is EVERYTHING during the tax season.  These seemingly little things make a WORLD of difference.