Under normal circumstances there'd always be a few members visiting Istanbul, either extending a transit or simply for a visit - this year I suspect not so many.
Anyway, if you are planning a trip it'd be advisable to avoid the Taksim and Beyoglu areas on Sunday as there is going to be a massive political rally organised by the nationalist MHP, with participation from the AKP and their supporters. Maybe Sunday would be a good day to stick to Sultanahmet, or head over to Kadikoy on the Asian side.
JF