You are right that it can't be an exit scam because even if the 8/10 people would accept the loan request then the amount would be 100$ if the amount is on average 10$. The amount could be earned in only 2 weeks. In this case, I do not think there is anyone who is in a signature campaign and the earnings are good based on the loan amount and would not default that.
I completely forgot about the sig campaign, but that also supports the fact that it is probably not an exit scam, unless that person does not think logically and just wants to collect as much money as possible and disappear.
I would call it shallow thinking on his side, how much does he possibly think he can gather and exit the forum that would be compared to the pays his signature campaign would give him, and more possibilities open to him as a forum member with Hero member rank? Did he forget that bitcointalk isn't a charitable organization?
Judging from the allegations against him, there were some elements of a dirty play in his conduct, I don't totally believe he needed the funds for the reason he stated, but he chose the wrong environment for his tricks. Let's all believe he learnt his lessons. He better knows that he might not be so lucky with such dirty plays next time, so he should apply wisdom henceforth.