There are plenty of people[1] that can perceive whatever PWM frequency is typically used in vehicle LED taillights. Like a few the people in the linked forum, the switching in the vertical Cadillac tail lights are particularly visible to me.
I agree that when viewed directly, it's quite unlikely anyone can perceive a switching frequency in the thousands of hertz. But if you sit in one of the closer seats, your eyes will be darting back and forth across the screen, which would be enough for that strobe effect to bother me if the frequency is anywhere near what is used in the taillights.
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