daf bit: Bava Batra 102

The mishna continues to teach us the importance of precise language. Last week we learned what is expected if somebody sells "a cellar of wine" versus "this cellar of wine". On today's daf the mishna talks about selling land.

A beit kor is a unit of area, 75,000 square cubits, which is the space in which you can sow a kor (30 se'ah) of seed.

If one says to another "I sell you a beit kor of arable land" and the land contains clefts that are ten handbreadths deep or rocks that are ten handbreadths high, he can't count those areas in the measurement. He can count shallower clefts and shorter rocks. On the other hand, if he says "I sell you about a beit kor of arable land" and it contains deep clefts or high rocks, it's all counted. (102b)

I don't see any discussion here about excessive clefts or rocks. Are there limits to "about" if it's nowhere near a beit kor of actual arable land because it's super-rocky or whatever? Or is it the buyer's responsibility to inspect before buying? (My main question isn't about fraud but rather about mismatched expectations.)