No.

Curious how an appraiser would even know it's a non-arms-length sale if the transferor and transferee names are different.

Any relationship must be disclosed. For example, if you were the agent and had a relationship to the seller other than purely professional, you must disclose this fact in the listing. Failure to disclose on anyone's part could be fraudulent and punishable by jail time by those who failed to disclose.

Practically speaking today, most properties are publicly listed in the MLS, use a realtor and are covered by realtors ethics, rules and laws. Because of this, I'm not likely to use a sale unless it's listed in the MLS.

Private sales are where you usually see a relationship that would not be arms-length. They aren't supposed to be posted in the MLS.

As an appraiser, if I am doing a private appraisal, I'm absolutely going to find out. It won't change my valuation, but I will note the lack of arms-length relationship in the comments. It's up to the lender to decide if they want to proceed. It may change their underwriting guidelines, should the purchaser desire a loan in order to acquire the property.

Any relationship must be disclosed.

Speaking of Ontario, where I was a broker for 17 years, on the listing, the broker/sales agent is required to disclose any relationship with the Vendor. But I'm not aware of such a requirement for vendors and purchasers to disclose on the Electronic Registration System for land documents used here. Maybe it's different in other jurisdictions.

I'm not likely to use a sale unless it's listed in the MLS.

Makes sense, as relatives transferring are not likely to be listing, selling and buying through real estate agents.

Can someone explain the arms length sale thing? What does that mean?

A non arms length sale means that there is no relationship between the seller and the buyer. In a non-arms length sale the buyer and seller might be relatives or have some other sort of relationship (business or personal) which might affect the deal. Lenders usually scrutinize non-arms sales more closely to make sure that nothing inappropriate is going on.

My husband and I bought our current house from his aunt and uncle. So it was a non-arms-length sale.

Can someone explain the arms length sale thing? What does that mean?

In an arms length transaction all parties must be independent and on equal footing. What it really means is that each party is free to look out for themselves. There is no duty to act to the other person's benefit.

Relatives are typically considered to be a related party transaction because they will often have other considerations than just this transaction.

There are ways to turn related party transactions into arms length transactions so they are not typically a problem unless you are trying to do something sketchy.

I think in this context it means someone paid less than market value due to the relationship, so that could potentially impact future appraisals in the area.

My dad sold me a $2000 car for $1000. That didn't lower the value of all $2000 cars.

Most non arms length transactions will never be in the MLS and depending on the location, the details are not shown on the transfer.

This question (and answer) is a location and unknown details specific question.