Late in July I have secretly basked in the glory of a CSP pre-qual which I plan to take up soon as my travel plans become finalized. Come August, I jumped the gun on one too many credit card payments and ended up with no balance across all accounts as of the 12th. In a couple of days' time my CSP pre-qual promptly disappeared! I couldn't be sure it was due to my lack of any revolving balance so I held my breath as one card reported a small balance on the 19th. Today (22nd) the pre-qual is back!
To think I am so close to the borderline that the lack of a balance could knock me right back to pre-deny-land 
Just a friendly reminder to everyone to leave a balance on one card if possible!