And let’s not limit this to fuel. Try calling it a day because you’re absolutely buggered and don’t think you’ll be safe by top of descent on sector 4 in your 13th hour of duty, or knocking back an MEL that when you throw in all the other factors, will seriously erode safety. Standard response from above is “its legal”, or “you can extend” or “it’s MEL’d so you can go”. The balance of power has reversed and now someone safely tucked up in an office and armed with a telephone can remotely usurp the command on a flighdeck they don’t legally occupy.