I know what You mean,
but such happens between People/Families who know each others very well and interact with each other's Families on regular Bases, sure not for a stranger or a neighbour which you greet passing nearby your place every other week.
I got last x-mas Eve afternoon from a american Boat ankering here at my place some great Fishing Tackle offered for a very good Price, US$3K total, sure I am not a Nuthead who keeps such sums in all currencies in the House, Pesos not suitable for a foreign Boat, so I went down to the Colmadon of our lil Fishing Town, told the Owner who in Town would have 3K$ handy before Dec25th 9AM(the next Day, when the Boat been sheduled to leave), he told me 'wait a minute", I took a Beer with my Buddy and 15 minutes later, when we ordered the 2nd Bien Fria the owner passed me a lil Plastic Bag over the counter, biggest bills been 50's, most been 20's, I did not count before I was Home(200 meters walk) several Beers later, sure it was exactly 3K$, no questions asked, not asked when and how it comes back. such is usual, but of course between People/Neighborus/Business Owners who know each others well.
the next working Day of course I went to the Bank, withdraw the money, stepped by the Colmadon for a Beer and paid the 'Prestamo' back.
for a near stranger, just a bit known, I would not give 1000 pesos for what ever reason and I would not ask a nearly stranger for any kinda sum to Loan Me.
Mike