It's really just a geography thing.  If I hadn't spent my tax career in a major metropolitan area, I might think it absurd to report every property sale.  But I didn't have that path.  Even the crappiest 1 BR condo around here is going to sell for at least $300K and I guarantee you there will be a 1099-S, whether the client thinks so or not.  Chances are it will be buried in the 200 pages of documents that were signed at closing.  There's no point in asking the client about it, they're not a reliable source of information on this.  If it didn't come in the mail at the end of January in an envelope marked "Important Tax Document" in their mind it doesn't exist.

So I report all sales.  In most cases there is a full 121 exclusion even if I just use the purchase price as basis with no improvements.  Counties/cities around here have all of the sale history online and it's less than 60 seconds to look up and print-to-PDF the property history.