[Avodah] Clever collector

[Moshe Y. Gluck]

Someone forwarded this to me, and I thought it might be of general interest:

Question:
A collector from an organization was nudging a gvir for a nice donation. 
Exasperated, he writes out a $100,000 check and hands it to him. Later, when
the collector discussed this nice donation with another future prospect, the
fellow laughed and said, I know for certain that there is no more than
$80,000 in that account at any given time, so you may as well throw the
check away for it's not worth the paper it's written on, never mind
$100,000!
Immediately, the collector called up his organization, who deposited $20,000
into the man's account and then presented the check for $100,000 and
withdrew all the money. Quite clever.
 
Question is: who's right?
 

KT,
MYG