It is doubtful anyone would be willing to find out outside of the Test Server.

Most Bards wouldn't even think of looking at a Lore other than Air, and given that you have to have 10 ranks of Fire before you get even a 1% chance it's pretty unlikely anyone's going to do so for such a crap-shoot. They could give up ~30 ranks (== ~6% chance of a second Sonic Weapon flare, from mid-30s % down to high-20s %) to get ~2% chance of a bonus...
...and then, only to spells that match their Attunement. I'm unconvinced that ANY of the BardSongs--even the ones that benefit from Air Lore ranks--are considered to be "of type Air", in the same manner that Minor Fire is "of type Fire".

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Bards have a LOT more return on investment for training EL:Air.

As I recently said over in the Wizard discussion, if I were to train in anything different (or get Enhancives for anything different), it would most likely be Water to get the walk-around benefit of +10 Mana Recovery from Mana Focus/418.