Well, I meant "would you join a late wagon", not "would you gather evidence".
But this work too.
The question is whether the observation "a player bussed" provides a measurable inferential effect on the proposition "the player is scum". This is a simple problem of Bayesian inference, and since we have numerical data, we can handle it quantitatively. Specifically, Bayes' theorem gives:
P(scum|vote for scum) = p(vote for scum|scum)*p(scum)/p(vote for scum)
p(scum) is found quite simply as the ratio of scum players to non-scum players on the days in question. During Crusader's vote there were 9 players (A Link In Time, musicfan, Linkdude74, Mellow Ezlo, Frozen Chosen, Spiritual Mask Salesman, Cody, JC-Hurin) and 3 (Eoghan, Hurin, and Cody) were scum. During Pendio's vote there were six players (Linkdude74, Batman, Go_Dark_Link, Blackkirby, Eduarda) and two of them were scum (Sadia and Eduarda). In the provided reference class this give p(scum) = 5/15 = 1/3.
p(vote for scum) is given as the ratio between the number of players on the wagons in question over the total player numbers, in this case 9/15=3/5.
p(vote for scum|scum) is found as the ratio of mafia members who bussed to total mafia members, or in this case 2/5.
So we have:
P(scum|vote for scum) = p(vote for scum|scum)*p(scum)/p(vote for scum)
P(scum|vote for scum) = (2/5)*(1/3)/(3/5) = 10/45 ~ 22%
Recall that we concluded the prior p(scum) to be 33%, so seeing that a person voted for scum has - all other things being equaled - actually lowered the credence to the proposition that they are Mafia by 11 percentage points, direct contravening the point you wanted to make with these data.
... Of course, I don't consider this by any means conclusive. The sample size is tiny and artificially selected, and we're not accounting for the "late to join" effect which had been discussed. I can do that analysis of you'd really like but I'm not particularly motivated to because - again - Mafia Is Antiinducitve and if an identifiable pattern really did exist then the game would evolve to remove it.
This is why I asked the question I did: would you, DekuNut, join a late bus if you were scum or do you consider it to much of a tell? For the sake of generalizability assume you're playing against a game-full of clones of yourself.