E-mail reply I received yesterday -

Thank you for contacting JetBlue Airways again regarding the exit row seats and how they are assigned.

Our A320 aircraft seat map has been modified to make sure our highest-paying Customers have the first opportunity to book certain seats. The following seats may be available to assign when a Customer books a Y, H or K fare on an A320. When a Y, H or K fare are not booked or the seats have already been reserved, the normal reserved indicator will be displayed.

2 A, DEF
3 ABC, F
4 CD
5 CD
6 CD
7 AF
10 ABC, DEF
11 ABC, DEF

Our E190 aircraft seat map has been modified to make sure our highest-paying
Customers have the first opportunity to book certain seats. The following seats may be available to assign when a Customer books a Y, H or K fare on an E190. When a Y, H or K fare are not booked or the seats have already been reserved, the normal reserved indicator will be displayed.

3 AB CD
4 AB CD
5 AB CD
6 AB CD
12 AB CD

We have done this as our business travelers frequently are notified they have to travel the last minute so they end on paying a higher fare. In fairness to our loyal business travelers we want to make sure they don't always end up in a middle seat. Hopefully this explains the new guidelines for the seating.