NIU will be in the bowls no matter what. There are only 58 bowl eligible teams right now, and 56 slots for bowls. This means that even if you eliminate 2 of the other 3 eligible teams from the MAC (Western Mich, BG, Miami), NIU still makes it in.
I believe the count is 64 eligible teams, so yes, it is possible that NIU could get screwed. They must win the MACC game. There will only be 2 MAC teams going bowling.
As for the BG sitiuation last year, the bowl counts were in and it was known that the MAC would get several bowl bids. It was also know that some of the other bowls would be just as attractive, if not more so, than the GMAC bowl. They only extended the offer to BG after the MAC had secured other tie-ins. The bowl organizers were scrambling and actually running to the MAC to get a team. While it was not known who would go where, it was known that we had secured the Independence Bowl and that one was to better than the GMAC. Also, MCB had first rights to the winner of the MAC. This opened the door for GMAC to select BG. The only teams not knowing if they would have a bowl were NIU and Marshall. It was known that BG, UT, and Miami would have a bowl game.
As for NIU, they were feeling screwed again this time last year. They had beaten us earlier in the year, yet we got the GMAC before it was known if the MAC would secure a fourth bowl. NIU was screwed the prior year, because they had a great year with 2 losses and still no bowl. Now here's NIU again, in a pretty shaky bowl situation when they beat the team that has already secured a bowl and they still have work to do to get in.