Yeah, if my rental experience has taught me anything, it's that the lease is mostly useless. Out of five apartments in town, I've had three bad experiences. In the first one my downstairs neighbors were violating the lease in about six different ways (including not paying rent), but my landlord didn't want to evict them because they paid more rent than we did. In the second one, my landlord was coming by at all hours of the day and night without giving notice, and it was Urbana law that protected me, not the lease. And now, the guy upstairs is violating the lease in at least a couple ways, but it's up to the landlord to choose if he wants to do anything about it.

And if those students didn't have a "failure to deliver possession" clause, they'd still have to get the landlord to actually PAY the damages, which he wouldn't necessarily do (at least in time to pay for the actual hotel rooms they needed.)

Incidentally, my current lease has "failur to deliver possession" in conjunction with a clause allowing me to break the lease after a certain number of days of undelivered possession.