SMART CONTRACTS, DEFI & WEB3 SECURITY - Chapter 4, Exercise 2 Solution
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Correcting "No Credit Check Means Safer" for DeFi Lending

PROBLEM
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A friend says: "DeFi lending is safer than a bank loan, since it
doesn't need a credit check at all." Using this chapter's own
explanation of over-collateralization, explain what's misleading about
this claim.

SOLUTION
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This mixes up two genuinely different things: not NEEDING a credit
check, and being SAFER as a result. The absence of a credit check isn't
actually a safety improvement in DeFi lending - it's the specific
reason DeFi lending requires a much stricter, more restrictive
condition than a typical bank loan does in the first place.

As this chapter explains, DeFi protocols require over-collateralization
- posting MORE collateral value than the amount actually borrowed -
precisely BECAUSE there's no credit check, no identity verification,
and no legal system to pursue a defaulting, pseudonymous borrower. The
collateral itself has to do all the work a credit score, employment
history, and legal recourse would normally do for a bank. That's not a
safety feature for the borrower - it's a real, restrictive requirement
that a traditional borrower with good credit typically wouldn't have to
meet at all (many bank loans require little or no collateral,
precisely because the credit check and legal system provide the
lender's real protection instead).

From the lender's side, over-collateralization plus automatic
liquidation genuinely does provide strong protection against losses -
that part is real. But it comes at the cost of a borrower needing to
lock up capital worth more than what they're actually able to borrow,
and facing an automatic, code-enforced sale of their collateral the
moment its value dips too low, with no grace period or negotiation the
way a bank might offer during genuine financial hardship.

ANSWER: The claim confuses "no credit check needed" with "safer" - in
reality, the absence of a credit check is exactly why DeFi lending
requires borrowers to post more collateral than they receive, a
genuinely more restrictive and risk-exposing condition for the
borrower than many traditional loans require, not a safety
improvement. It's a different risk trade-off (automated, collateral-
based, code-enforced) rather than a strictly safer one.

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WHY THIS WORKS AS AN ANSWER

This separates the mechanism (no credit check) from the claimed
outcome (safer), correctly identifying that over-collateralization is
the direct consequence of skipping a credit check, and that it shifts
risk onto the borrower rather than eliminating risk altogether.