1 - The purpose of a point spread is to keep the book balanced. To have an even amount of $$ bet on both sides of a proposition. The house makes a 10% vig on all bets. It wants to be able to not care who wins. Anyone who tells you "Vegas needs the Lions and the Bears this weekend" knows nothing about sports gambling.
2 - The handle on Marshall - Albany, worldwide, could not have been $10K. Most books do not even offer points spread bets on I-AA @ I-A games. Because the pool is so small, it does not take much money to get the book out of balance and cause an adjustment. It is not necessarily sharps doing this. More likely its is dumb money MU superfans.
3 - Again, the handle on something like MU @ ECU is not much, and it doesn't take much to move the line. Sports gambling is legal in WV, and not yet in NC, which just that fact can get the line out of whack. Only a handful of superfans can mess things up.
If you want to gamble it is MU -3 O/U 44.5 ML -155/+130. ECU was outmatched vs. Michigan, and we did not learn much from that. We learned a lot from the SUNY Albany game. ECU is a mid-pack team in the weak AAC, MU is one of the worst, least talented, most poorly coached teams in the division. Don't bet the house on this game, there is lots more value on the board elsewhere, but ECU moneyline and under are logical bets.