I was always under the impression that that was how it worked, but it seems like it's untrue.

The EFL regulations state:

"3.3.1 unless otherwise mutually agreed in writing, all tickets shall be on sale or return basis;

3.3.2 payments for tickets sold by a visiting Club together with details of tickets sold and the return of unsold tickets, must be made to the Home Club within four days of the date of the match"

There's clearly some negotiation from the club in terms of what they anticipate actually needing and that probably plays into the restricted allocations we've seen recently, even for fixtures where we're entitled to a larger number (the minimum entitlement is 10% of the ground capacity or 2000, whichever lower).

Given there's seemingly no cost to the club, it's bizarre that we aren't just taking the full allocation we're entitled to for all games and then just returning the unsold tickets, rather than drip-feeding them.