Notice that there's a 'rec' indicator in the front panel display, but it won't light when the T3 is in standby ?
It's also a pretty small and hard to see at a distance.
There's a nifty parameter for the front panel display 'skin' that will flash the clock while the T3 is recording in standby mode.
This parameter isn't visible in the setup menus, so you'll have to add it manually.
Add the line:
config.usage.blinking_display_clock_during_recording=true
to the /etc/enigma2/settings file, and restart the GUI.
I found it useful to verify at a glance that a scheduled recording runs when the T3 is in standby.
Alternatively, ask our T3 developers to add this parameter to the setup config in a future release.