I just was thinking back to when I was in college...the fraternity houses were off campus and generally very open. Anyone could pull up to the house at any point and just walk right on in, no questions asked. I would imagine houses w/ a house mother would not be that lax.
These houses were (as I'm sure most fraternity houses are) old and very rickety...and a few of them probably should have been condemned. I know that one of the houses did burn down about 2 years before I got there - and all people would mention when that subject was brought up was what a great party that was that night.
Of course, I wasn't in any of these fraternities, so I don't know what types of fire drills or risk management procedures were in place...but I did spend quite a bit of time at one or two of them (only during the day of course

), and there didn't seem to be anything like that in place. I specifically remember one house had a fire extinguisher next to the kitchen, but every time it was replaced, it seems they'd get drunk, pull it down and spray it all over the house so the pledges would have something to clean up, or just b/c they thought it was funny.