I'm not too sure if the question makes much sense, but let's assume that you get a job offer in SF, and in order to accept, you basically have to sign a 6- or 12-month contract for rent in order to be close enough to the place of employment, where the rent for a 1-bedroom apartment in SF is currently at an average rate of 3.6k/month (e.g., some 2.5k/month more than the rest of the country), whereas your relocation and signup bonus may or may not cover all such rent for the whole 6-months of the minimum lease term.
Realistically, with the employment being at-will, you can be fired at any time, including even before your first day at work — companies fail, projects and requirements change, folks move on, decision makers get questioned — happens all the time.
In this sample scenario, would it be correct to refer to the rent in question as an example of an unfunded liability, or partially funded if it's not fully covered by the relocation and signup bonus allowance? Why or why not? If not, what is it then? When does the liability become funded or unfunded? Does it only become unfunded only if the job is lost, or is it always unfunded if there aren't enough money in the bank account to cover the liability? And if it is unfunded, at what point does it become funded?