Some rely on BPOs, others prefer full appraisals or internal comps.
What’s your go-to method for validating property value before buying a note?

Judgments and liens are far more valuable because they are attached to collateral and clouds title.   

The first people that lose their money in a downturn are those that are lending at insanely high LTVs without adequate underwriting experience including determining if the borrower's qualifications based on credit/character, capacity, and collateral.  

.• Hard money / bridge financingFor flips, lenders care most about your scope of work, ARV, and collateral.

I saw some of his videos about inflated loans on specific properties but the loans were for acquisition and renovation or cross collateralized, so for the average person they would see the video and be like OMG, but as a sponsor and investor, I shake my head. 

They purchased using a program that finances 100% of your purchase/rehab on paper, and takes a 15% deposit as cash-collateral that they hold until you refinance.• $60k purchase• $35k rehab• $95k total rehab loan payoff• 15% deposit = $14,250 "down payment"• $126k ARV (confirmed via refinance appraisal, borrower expected this to be higher)• 80% rate/term refinance ($100,800 loan) @ 6.75% [700-719 FICO]• Applied $4k of deposit to payoff for an updated payoff amount of $91k• Cover closing costs with 80% r/t refi + $2k back to borrower at closing (still considered a r/t refi if under $2k) + remaining $10,250 deposit reimbursed after payoff = $12,250 total back to borrower• $4k of his deposit + closing costs for rehab loan = his "cash" in the deal• $1,250 market rents• Total PITI = $765.62• DSCR = 1.6327 I do not see the hold costs.  

Yes, I do understand that the experience may be a mild deterrent for lenders but I I will refer to using the land equity as a form of collateral.

My local bank does not do it since it’s not fixed to the grounds. My local Credit Union also doesn’t do it, but didn’t state a reason. I’m located in New Jersey. Does anyone have any experience? Or is that the standard?

Because they can take smaller profit margins via the power of scale and cross collateralization of liabilities on a pool far bigger than any standard landlord can. 

In banking the only time we usually did a 2nd on a commercial space is when we were 1) cross collateralizing, 2) the customer was a really good client with significant deposits with us, or 2) we would already give that person an unsecured line and we're grabbing the property in an abundance of caution.