I live in Baku - Azerbaijan but not riding my bike here as I am a Turkish (foreigner too) and so not have any experience with 72 hrs limit.
I also heard/read about it, but only heard.
It is not easy to receive definit information from policemen or other places. When you face this problem in the border in or out you will experience all and we will learn better after your sharing.
Will try to ask someone about this but not easy...
"where the traveller goes, nobody knows ! "