Glad the transmission oil issue wasn’t a major event. Stuff like that always makes you take a step back and slow down.
A few months ago I was pre-flighting our R44 to go do some rides at a local fair when I found some hydraulic fluid had dripped and run down the tail rotor pushrod near the M/R gearbox. Additional prodding revealed a good bit more fluid had also run down the wiring harness there and pooled near the firewall, then run down it into the engine bay. Then more fine specks were found thrown all over near the accumulator as it dripped on to the T/R drive shaft. Turns out the pump was leaking, as was the return line to the accumulator. If I’d just done a quick visual inspection and called it good, I might have missed the leak, but I stuck my hands on every fastener, component, and crevice I can, and it paid off. Hydro failure with a load of pax into a tight LZ is not my idea of fun…
If your hands aren’t dirty/greasy after a pre-flight, you didn’t do it well enough, IMO!