While I’ve only visited a few cities in mainland China, the food delivery drivers that I have see have all worn open-faced helmets like this:
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As to why, apart from it being generally anti-social - it’s mainly because it’s a massive security issue, as the individual in question cannot be identified in the event of assault, theft or order crimes.

I am assuming that’s a GTX 480 and not an RX 480; if so - kudos for not having that thing melt the solder off the heatsink by now! 😅