I had e+ access for 1 year. Bought in April, ran out 1 yr later.
The website then said that if tickets were purchased while e+, would be valid for upgrade and I chose my e+ seats.
14 months later, DEN-KOA, the e+ ran out and we were in e- in the middle after a sweep, but the return was in e+ and was not disturbed.
YMMV.
YMMV indeed, similar thing happened to my wife. She had E+ access for a year that expired in February 2010. I booked awards using my miles for her and little Ms. OU812 in December 2009 for a flight in late March 2010. They were booked in seats 6AB on a A320 IAD to LAX and seats 21HJ on a 777 from LAX to IAD. I kept monitoring their seat assignments up until OLCI was available. Luckily, their sears were never touched.
Regards,
RIP