Business is business...if I am selling for a business, it’s not MY business who buys what...only that I make enough to cover my cost and keep my employer happy (if I am working for someone or on commission).
There is nothing wrong with giving guidance - telling someone what may or may not work for them or considerations. You also need to stop there...their money - their free choice. What may sound stupid to most people may be sane to them.
Now to me - selling privately, I am a bit different. Friendship and good relationships come first. If I don’t think it’s a fit - I just say not for sale...in a polite way....maybe I “changed my mind” or “ just sold it...guy gave a deposit to hold here”. - but I find a way out. Problem is - moment you post it or hang a For Sale sign....you need to approach things like a business....it’s the ones where I’ve got something sitting around and someone eyes it and offers that I can back out of selling....otherwise it’s tough.
Also always remember the old used car salesman saying “Buyers are Liars” - it’s true many times.....they will come to you with a story, and it seems they are over reaching for their intended use....they try lower your price and possibly do a little.....next thing you realize they are reselling at a higher price.
Happened to me once on a tractor...kid stopped out and looked at an old Allis Chalmers I had...my old man traded fo it a few years before and when he passed, it became my headache. It was actually fairly nicely restored by the prior owner. Just not something I had a use for at all though.
Anyway, kid calls me and ask can I help him out - he needs a project for school....he knows this is a prior restoration that runs, but just needs something to demo he can do mechanical work on an older machine with and show off at a project fair....said sure, it’s a worthwhile cause and I practically GAVE it to him...knowing cash buyers were few and far between.
Low and behold - he gets it, 2 days later it’s posted on CL in for sale/for trade....wants 5 grand or trade for motorcycle, UTV or firearms. Complete BS story how he lovingly restored his grandads tractor, single owner...hates to sell but grandad passed and too many memories as they worked on it together.
Had a buddy correspond with him and fake an interest. Got a meet set up and took a ride with my buddy to meet the kid at his parents farm. Needless to say - he was surprised to see me.
I know it sat forever...he kept reposting for weeks, eventually went away. Guess he found his Buford. Certainly played me for one too....which sucks because for everyone of these punks, there still probably are 9 kids legitimately just looking for a break and helping hand.