[mattwad]

There are checks and balances built in. For example, if you offer too much money, and the appraisal comes back and says it's not worth that much money, then your loan will not cover it and you will be on the hook to cover the difference.

[Guvante]

Only in instances of fraud, at least effectively. Appraisals defer heavily to "this person is willing to pay $X to this unrelated person for this exact house".

If they can find someone paying more for a nicer house and someone paying less for a worse house you are likely going to be in the clear.

Technically they are supposed to adjust to get your home value from comparables but the magic "market adjustment" means that they can basically always do that.