Could be some entirely different scam? Like they could write cheques in the names of old people with lots of money in the bank, then, if some people cash them in, they could approach them and ask for their money back. If some people comply and don't check carefully who the money originated from, they have extracted some money from random people who may or may not have noticed it. Not sure how cheques work in the US,…
[1] Auctions for example, where the payment must be delivered immediately and cash would be impractical. Usually, in that case, a "Bundesbankscheck" is used which is as good as cash: http://de.wikipedia.org/wiki/Best%C3%A4tigter_Bundesbank-Sch...