What if you just lie to the ticket inspector?

I wouldn't ever do this. I buy my tickets and always have a valid Railcard.

That said, I've always wondered - if you were caught without a ticket/Railcard, what is stopping you from just lying to the ticket inspector when they ask for your details?

Why can't you just give the name and address of someone you don't like, or just completely make one up?

(Again, I don't endorse this and would and have never done this myself - but I'm just curious).