To follow up some more, the full set of data for last year in the link that LtPowers provided (
http://www.uscho.com/stats/attendance/division-i-men/2012-2013/) shows that pretty much no team sold out all the time. North Dakota, Minnesota, Notre Dame, Cornell, Quinnipiac, and Princeton are the only ones within a percent or two of doing so. Our arena is supposed to be 4600 (I assume with standing room) and looking at others roughly that size you get Dartmouth at 75%, Bemidji at 74%, Mich. Tech. at 73%, and some others with similar numbers. We'll be at essentially the same capacity as Cornell, but I suspect it will be a long time before we have their number of season tickets, etc. I think it is very reasonable to expect the RIT average attendance to be about 75%, or around 3500, and that would be quite a success (and make the arena look much more full than empty). Such a number would also put RIT in the top 25 of attendance for DI.
It will probably be a rare game for which someone can't walk up, buy a ticket, and have a seat ... but they will happen (just like most of the last 30 years actually!).