for the sport of it, i signed in and got Orch row T, on the side so i can confirm that more than lawn was available. i threw them back. second pull = lawn only, so one had to be FAST. i did it to keep my ticket scoring skillz fresh.
presales sometimes have the best tickets and sometimes they have the worse. people who are chomping at the bit to get presale tickets are obviously very eager to buy and thus might settle for crap seats. a band might use this approach if they don't think they'll sell out a venue. wilco obviously don't have this problem. maybe they see being able to secure a lawn ticket as something of a benefit for their fans?
a trick with frontgate: be sure to be signed in before the presale starts. otherwise they make you sign in after it starts but before you can pull tickets, thus wasting valuable seconds.
to be honest, i dont see the point in a presale at all
i've gotten AMAZING seats over the years through presales. love 'em, but gotta know how to work 'em.