Mine appears to have been upgraded for free to the 75 as well. I do not believe that I have received a notification from Tesla regarding this apparent temporary upgrade.
I am still not pleased about the 3% battery degradation after 5 months and only 9K miles. I lost 2 miles overnight the other week when I ran down to 1%. I charged to 90% and 2 miles had immediately disappeared.
When new, I started at 189 miles at 90%. That quickly dropped to 187, then 185 and now 183. Most drops occured over a few days. This most recent was immediate.
I notified Tesla via their service email and thought they flipped the switch for the portion of the locked battery, but also thought it had something to do with Irma and this thread confirms that.
I know battery degradation is high during the first thousands of miles, but quick losses are painful.