Key Lock for ELV OG-100 Tracking Device (Ortungsgerät, Tastensperre)

I found my ELV OG-100 tracking device (Ortungsgerät) often to be turned on or with battery empty when taking it out of my toolbox. The keys on the device are placed really bad protruding from the surface itself and each key being able to turn on the device. The only solution for me was to design a key lock (Tastensperre) glued on top to prevent the device turning on by accident.