VCs can just talk to each other and figure out that you're a fraud, which alone is a great reason to not deal with you.
Don't lie! Morality is not just some arbitrary thing that you can make up as you go along if you want to achieve anything. The proper standard of morality for you and me and everyone else is not what will help or hurt the other party, it's what will help or hurt you and your long-term rational self-interest. Lying will necessarily prevent you from succeeding; see chapter 4 of Tara Smith's book, "Ayn Rand's Normative Ethics", which is on honesty.
VCs can just talk to each other and figure out that you're a fraud
That's the danger: getting scumbagged behind your back.
How is that "fraud"? Claiming you have customers you do not is fraud. Promising to deliver a project that you cannot or will not is a fraud. Claiming that other VCs are interested in you is not fraud; it's just the kind of thing you have to do if you weren't born into connections.
The only people who have a problem with that are silver-spoon assholes who want to keep doors shut to people who didn't hang out with them in high school.
People that are in business and successful because they were in a high school clique?
Just how many people does Steve Jobs hire because he knew them from school? Zero, because his way of doing business is to hire the best. To the extent that people are like Jobs in this regard, their businesses are successful. People that hire friends, regardless of their ability will never rise to great heights in business (or any endeavor).
Do you want to work for someone mediocre, or someone great? Even if you were successful in your lie, lying would only get you the mediocre job. A great employer (someone of high caliber) would figure it out, or would be principled enough to fire you when they figured it out.
People that are in business and successful because they were in a high school clique?
I never said this. Obviously, it is not true.
I said that the people who'd consider it some kind of moral transgression, rather than a strategic move, to tell a VC that you have other VC interest are the kinds of people who want to keep "the doors" closed to the hoipolloi, because their worst nightmare is outsiders getting into their club, so they have to throw into place a moral "consensus" that judges such moves to be wrong.
Don't lie! Morality is not just some arbitrary thing that you can make up as you go along if you want to achieve anything. The proper standard of morality for you and me and everyone else is not what will help or hurt the other party, it's what will help or hurt you and your long-term rational self-interest. Lying will necessarily prevent you from succeeding; see chapter 4 of Tara Smith's book, "Ayn Rand's Normative Ethics", which is on honesty.