From what I've heard the ground staff get 50p for every bag they disallow which then has to go into the hold
Not true.
Airport staff are being offered a 50p bonus for every Ryanair passenger they catch with excess baggage.
"Employees of the baggage handling contractor Servisair are given 50p for every bag they identify as overweight, though they are only eligible for the payment once they have reached a target of 10 bags in a week, it has emerged.
Under this agreement, Servisair workers can earn an extra £5 each week — they will not be allowed to go over £5"