it's not too harsh, but if you really don't want to get any problem then don't sell the account in the first place. if the new owner ended up scamming then some people will still blame you anyway for selling the account and others won't even believe that you sold the account (fake trade).
What you are telling is true , even if you take lot of caution steps if the users scams after some time then you will only be blamed as who ever is going to deal with your account wont know that it is you or the new buyer, as you cannot state that this account you have sold because then no buyer will buy it. So it is not good to sell your account.
