You say that, but I went to Man U and Liverpool matches at the Goldstone, in 1980/81 & 1981/82, never bought a ticket, just turned up and paid at the turnstyle. If there was that much demand then surely this wouldn't have been possible.
How was it it easy to get in without [a ticket] or paying? I always found a grotty little wooden door you had to pass through, pay over your wedge, then push through a rusty turnstyle, can't think of any way to get in otherwise.