ooh, I suspect the actors had fun with it, enjoyed having a change of pace, demonstrating (or attempting to demonstrate) more of a light comedic touch than their characters typically get to display. I usually don't think much of that Green Arrow/Oliver actor, but he pulled it off better than I thought he was capable.
Major line reading f*** up in this episode, however. Not so much that the line was botched, but that they didn't bother to do a re-take. Very sloppy. I don't know if it demonstrates severe budgetary issues, general disinterest from the show runners/production as the show nears the end... or something else. But I don't recall ever seeing something like that in ANY show before.
Specifically, when Tess was tracking the location of Oliver and Lois at Watchtower she states, "Clark, the nanosecond that they use technology will have their number."
She botched the line reading as obviously she was supposed to say, "the nanonsecond technology that they use...".
Anyway, goodbye Chloe. You had quite a run on this show. Clearly, the best actor of the bunch (at least amongst the more youthful group of cast members, excepting perhaps Erica Durance/Lois). It'll be interesting to see if and what kinds of acting jobs she'll get in the future. I don't recall seeing her in anything else during the run of Smallville. Can't bode well...