Somewhat amusing to see status and class work its way into access rules for lavs.

It's like the airline version of the aristocracy, the lesser nobles, the peasants and so on, except all played out in a "carbon composite" tube at 40,000 ft.

Single-aisle or narrow body aircraft with all of the Y lavs at the back might make sense for design, engineering, and plumbing purposes, but they suck for the average pax.

It's always fine dance FAs and pax engage in when carts are blocking that single aisle and someone "has to go".

Anyway, IMHO, the biggest problem with AC lavs are the sticky floors, mess around the toilet seat and so on.

(And be grateful Ryaniar CEO Michael O'Leary claims he was only joking when he wanted to charge for lav use on their flights)