Whether one chooses to interpret the sparking as derived of more passionate emotions or a sign of impending slapstick more on-tone with the canon, I am still left with a question:
Why was the note signed anonymous? A Kuroko willing to go this far seems unlikely to not simply sign her own name to the tag on the 'present'. The best I can think of is somehow it's the result of Misaki choosing to wingman in some manner.