airlock = nothing to do with beer being 'done' or 'ready for secondary'.
get your hydrometer out. take a reading today.
take one tomorrow
take one sunday
if all 3 are the same, the beer is done and good for secondary. that's the rule. 3 days of consistent hydro readings which are close to your estimated final gravity mean its done fermenting.
vibrations from a truck driving by outside, or a shift in room temperature will release CO2 in the beer causing airlock activity, days after a beer is 'done fermenting'.
Primary: English Mild
On tap: Pale Ale, Lancelot's Wheat, English Brown Ale, Steam Beer, HoovNuts IPA
Bottled: MOAM, Braggot, Raspberry Melomel, Merlot, Apfelwein, Pyment, Sweet mead, Cabernet
Gal in 2009: 27, Gal in 2010: 34, Gal in 2011: 13, Gal in 2012: 10