Threads like this remind me of a line from a song: "When will they ever learn, When will they EV-ER LEARN" (Blowin' in the Wind)
Lots and lots of threads here about the danger of plugging into 30 amp outlets other than at RV parks (And even there in some cases) without checking voltage first.
Many professional electricans see that outlet and wire it for a dryer, Air compressor, Welder or other 240 volt device (The outlet clearly says 125 volts max on it).
I wired my own,, properly,, Triple checking all connections,, No problems.