For starters, nobody should lend to someone with a history of defaulting loans. No, the lender doesn't need to stipulate anything around the price of BTC. If the borrower takes the payment in bitcoin and agrees to make the repayment in bitcoin, that's the end of it. How did this 50 (or 100??) Euro's come about? Bank transfer? Mailed him a note?
Neteller, according to OP.
The lender should have had a stipulation that if the price of btc were to rise to a certain amount that the loan needs to be repaid or the collateral will simply be kept by the lender to cover the loan, and then used that 50 eur to purchase sufficient btc. Or when the loan became overdue, the lender should have used the collateral to cover as much of the loan as it could as of when the loan was originally due, especially if the borrower was no longer responding to PMs
As I understand OP, the "collateral" was handed over to the lender at the moment the loan was supposed to be repaid/the borrower was already late with repaying the loan.
It's a late loan and he have 50 euro as collateral (that cover not less than 80% of loan value). Then he send me first, a lot of time, amount bigger than 0.08 BTC and never had an issue, as he could confirm. So stop accusing.
I'm not the one accusing, OP is. Then again, this thread is titled "defaulted on a loan" and not "is late repaying a loan". Anyhow, not going to argue over words here, it makes no difference to the situation.
But if we're at it, what's about your past loan defaults, say this one (
https://bitcointalk.org/index.php?topic=1340291.msg13670896#msg13670896)?Are you also just very very late on them? It's been half a year, that's just a "late repayment", not a "default", right?