A family strugling financially gets 250.000 from google but can never contact google because they are so difficult to reach but also can never use the money for fear of google noticing at some point and asking for the money back. Bank freezes account for suspect activity, irs audit and all kinds of hell...
There's two reasons why the time frame is so short: 1) "It's their own damned fault." There's an expectation that of all the institutions that should have 100% control and visibility to all of their transactions it's banks and big businesses. 2) The longer funds have gone unreturned the more expensive and time consuming it (usually) is to trace where the money went. I don't know if one year is the optimal period for such tradeoff calculations (probably not) but it is what it is.
Anything above $10k triggers a bunch of bureaucracy but the money that causes and therefore to deal with this (lawyers, accountants, etc) is not theirs to keep.
They could end up paying thousands in fees, and have to wait years to get $80K back from the taxman