Yes this was true.  As an operator of these machines we lost plenty of takings and on some occasions coin mech was damaged, so double loss to us.  Also had the wire or icy pole stick down the coin shute trick tried but most times all it did was block up the mech.  I can remember another occasion when doing collection I found a whole lot of collectable coins from other countries as well as Aus. - some kid would have been in the s..t when dad found out, lol.