Wishful thinking, unless you are flying an E190.

If F9 did that, I feel that it would make the Stretch Seats seem more like a premium cabin. In addition, they would have to take out eight possible revenue seats... Perhaps we will see F9 do this someday.

On my return flight this last week, I was sitting in 5C on a fairly empty flight. A family of four boarded - the father and one child were seated next to me, while the mother and another were seated a few rows back. Since there was an empty seat across the aisle from me, I offered to move so they could all sit together (this prompted angry glares from the gentleman in the middle seat across the aisle who apparently wanted the aisle seat instead, with an empty middle seat - whatever). During this process, I asked the flight attendant if I could move up to 4d (there were at least 5 empty stretch seats) and was informed that I couldn't. I told her I was a Summit member and she informed me that she wasn't supposed to move up anybody into those seats, "even Summit" members. I was a little taken about, but she did eventually let me move up.

Only once has Frontier called me up during pre-boarding to ask if I want stretch seating (I almost always fly in 11D exit row). I find if I don't specifically book it, it doesn't get offered, even if they're empty.

Was there no stretch seat available when you booked ? You can now just select them at the time of booking. Also during check in did the seat not show ? The last 10 flights or more I always got the seat either during booking (after they allowed this for free for Summit members) or at online check in.

I almost always book through the official site, but for this particular trip I had to book through Expedia in order to get the itinerary I needed (fly out on United, back on Frontier). At least I was able to put my ER number in my itinerary.

Irrespective of that, though, is my point about the FA telling me she couldn't move me (I was just trying to be nice, I would have taken one of the seats farther back that the family vacated, it's just that so many seats were open in front of me), even though I was Summit. If Summits get those seats free, then why couldn't she move me?

I agree with you... you should have been moved up into the Stretch section, especially if you had your Summit card, or at the very least, your boarding pass with Summit printed on it.

Boarding priority?
 

Is there a standard system-wide boarding priority for Stretch Seating? I flew SFO-DEN-GRB and return over the weekend. I was late arriving to the gate SFO-DEN so I missed any priority boarding. The DEN-GRB did not have preboarding for any passengers other than priority and those needing more time, as far as I could tell.

On the return, rows 1 and 2 were included in the preboarding at GRB (Republic E190 with 1 x 2 seating in Stretch / Signature) and all Stretch Seating was preboarded for DEN-SFO.

If priority boarding will be a standard benefit of Stretch Seating, it should be noted in the amenities. I definitely would be more likely to upgrade if this is a benefit.

I flew MKE-BOS (Frontier Airbus) last Friday and there was priority boarding for Stretch Seating passengers.

I think they are supposed to board rows 1-4 after Summit/Ascent members, but not all agents at all locations do it.

I suspect there will be some adjustment time for the agents to get used to the new policies.

Give it a few months to become uniform.