3 way lamp says If you install any single watt bulb in a 3-way lamp there is a possibility of bulb malfunction leading to danger of fire.?

BULLSHIT. Been doing this all my life. It just means the switch needs to be clicked twice to get the lamp to light.

Green 666 by isotope rays is NOT forgivable; it leads to permanent hell. 666 is given with World Passport with no name on it (grey plastic card). Police 666 people on highways. Food stores and prisoners/insane asylum folks (released by the antichrist) 666 people too. Reject vaccines. Don't go into UFO to be “healed” by evil demons. Hide with Orthodox Christians to escape 666; leave all electronics behind so that antichrist's minions can't track you; burn documents as documents are from Satan.

Try it and let us know how it goes.

No, it says NO SUCH THING. I don't know exactly what you misread, but that claim is PURE BS.

No way that is true. You can use a single watt bulb in a 3 way lamp with no danger of anything bad happening. 

That's baloney.

A single-power lamp will work.  Likewise, a 3-way lamp in a single-power fixture will also work.  You just won't be able to use either the lamp's or the fixture's full capability.

sure seems like nonsense to me ... i've done this sort of thing for decades without trouble.  ordinary light bulbs, correct?

Its just a manufacturer cover your *** warning..

Just like gorilla glue will probably be adding don't use in hair to there label. 

All warnings should be removed so darwinism can do its job.

If it’s a standard incandescent bulb with an E26/E27 base, you should have no problems. Three way bulbs have two filaments and three contacts on the base, where single watt bulbs have only two. On a three way bulb, there’s an extra ring on the bottom which makes contact with an extra contact in the lamp base. This extra contact is how the lamp has three intensity settings. Any UL listed bulb should be manufactured to specs preventing contact between the outer neutral contact of the bulb and the intermediate contact of the three way lamp base. An improperly designed single watt bulb could potentially have a neutral contact that would touch the intermediate contact and cause a dead short. This would definitely be a fire hazard if a breaker didn’t trip. The lamp manufacturer probably put that warning on there to release them from liability should there be an issue.