A couple of Winters back the guys who had joined without TR were given the choice , take 4 mths OFF unpaid & come back, or leave, but you have to pay back the TR. The Union eventually got it diluted to less unpaid time off, and some people were given 50% with the salary deductions for TR suspended.
Some bods did indeed get back into RYR, depends on the circumstances in which you left, never burn bridges being the lesson. In most cases they had left to avoid taking low paid Command upgrade / base change & came to NAS with promise of rapid command which didn't materialise, so , felt it was better to retry "the devil you know" finally.