Well, all good points have already been made. The 'Chris-and-the-kryptonite' thing as it was (which is way beyond suspicous) as well as the media's anonymous tip and Lana's unexpected presence. So, there remains the question: Was it Lana? Or someone else?
Pro-Lana arguments are her behaviour after she knew Clark was married to Lois: Trying to seduce him, going home with Lois and Clark during spring break, cornering Lois beforehand, 'playing the field' and getting pregnant herself...
Of course, it might have been Navance and his evil goons - but would he have known about PopPop's death and the date of the service, much less in time? Does he even know where Smallville is? Besides, the wording of the anonymous tip sounds pretty much like the story Clark originally told Lana.
Contra-Lana: There is no contra-Lana. Period. I was going to mention Lana being accompanied by Tim, but, as a matter of fact, Tim is not mentioned in this part... So, maybe they broke up and now Lana is trying to break up Lois and Clark?
On another note: When will Lois and Clark tell each other about their 'dream' in the cabin?
