Two things: 1. Do you turn off the receiver when not in use, or does it just stay on? It doesn't seem to have an off switch, other than just unplugging it... 2. The battery powered transmitter pack won't turn off right now, but is saying the batteries are low, is it not going to turn off because it wants me to change the batteries? Had it for 6 months and never been unable to switch the pack off before... Thanks in advance for any replies!