It will light OK, but you could get into big legal trouble. When the
inspectors come to see if you still have all those "Do Not Remove Under
Penalty of the Law" tags on your pillows and mattresses, they will cite you
for a standard bulb in the fan. None of my business what you do, but I'd
not take the chance.
Of course it's safe; the only real difference between "fan rated" and
"normal" is that the fan-rated lamps can handle the vibration better. If it
requires a stepladder to replace the lamps, then that would be an argument
for fan-rated lamps, otherwise use the regular lamps.
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