I don’t think you’d be as heartbroken as the tenant that lives there and would like to stay so much they want to buy it.
I thought that too. Plus, if the owner knew that their tenant, with whom they already had a relationship, wanted to stay in and buy it, and was willing and able to pay the asking/best price, I personally don't think very highly of their moral stance (others will disagree with me, I know) to still go ahead and put it on the market - unless they were hoping somebody might come along and offer them a shed load more.
Put it another way: the resident of the house (and also their family, if they have one) were previously renting it, but now they're in a position to buy and the owner wants to sell. There's nothing at all legally wrong with wanting to sneak in there and take their home from them, but I really don't think I could bring myself to do that.
Plus, as PP have said, the hassle if the tenant doesn't leave without a fight - certainly not unlikely if they were hoping to be able to buy it themselves.
Also, the lie about the parking is quite a significant one, and suggests a less than scrupulous seller. It's quite a thing to suddenly remember that your property doesn't have parking after all; and it never happens the other way, does it - "Oh, yes, there's an extra double drive at the side as well - I'd completely forgotten to mention that one before, as we only ever park our shared hatchback on the front drive."