Dan ran this race with one intention: sub 27:50.
The only possible way that someone can qualify for the olympics with a B standard is if they win the race and 6 of the 7 A qualifers drop out... Not gunna happen.
July 4th (the day of the Trials 10k) is the last chance for runners to hit the A standard. The B standard is virtually worthless (other than the novelty of it). It seems unrealistic that anyone would hit the A standard before the Trials since opportunities have pretty much run out.
In all likelyhood the only people that will be running a 10k before the trials are those running at NCAA nationals. Of those Quigly seems to be the only runner with the capability of sub 27:50 but NCAA's will likely be tactical but even if it isn't since Quigly has the fastest time in the field the only way he would run that fast is if he did a lot of the work himself.
Therefor if anyone wants to go to the Olympics that hasn't already run sub 27:50 then they have to do so at the Trials and they have to be top three at the same time.
That said, the possibility that the Trials race is fast is pretty high since a fair number of quality runners have not hit that mark yet and will probably sell themselves a bit for the chance to go to China. These runners (in my oppinion) are Fasil, Rohatinsky, Brown, Summerside, Tim Nelson, Quigley and possibly Culpepper or Dobson if they run. Rupp or Meb or another one of the A qualifiers might be interested in making the pace fast early to try to eliminate some of the competition but there is certainly no guarantee.
In all likelyhood the people with A qualifiers (Abdi, Rupp, Meb, Torres, Carney, Moran and Bauhs) will sit and go for a ride for atleast 15 laps or more. It is in their general interest that the race is tactical because that makes it a race between 7 people rather than a race between the whole field.
It is a huge advantage for the runners with the A standard since they only have to focus on competing with the other runners rather than the clock. In all likelyhood the top 3 in the race will probably come from these 7 both because they are generally more talented than the rest and because of what is already mentioned, but it is even more likely that the 3 going to Beijing are from these 7.
That is why Dan Brown ran this last weekend. The 28:05 is worthless when it comes to qualifying to the olympics (it does show that he is in shape and he may have gotten some sort of performance bonus for it but that is it).