'Retrenched' is the present day equivalent of 'laid off' throughout Australia. I've never heard of 'riffing' or being 'riffed'.

Throughout my 7 years in the people business (recruitment, outplacement), it was critical to stress the differences between retrenchment and redundancy. There is strong potential to erode people's self esteem if these words aren't used carefully. Frinstance, recent retrenchees (still trying to cope with the emotion of the situation) would often say, "I've been made redundant". This can become a process of negative affirmation unless nipped in the bud so we were trained to chime in immediately with, "No, you haven't been made redundant. YOU aren't redundant, you have been retrenched. Your previous POSITION has been made redundant". People seemed to appreciate the sentiment.