Maybe - was this her first time having coffee at McDonalds?

I don't know. And I don't know whether this particular time the
temperature was hotter than most other times at that same McDonalds.
This is not evident on first viewing, certainly not evident in the
newspapers.

Would anyone change their behavior if there was a warning on the cup that
said that the coffee was hot enough to cause a serious burn? - I doubt it
based on the kinds of accidents that happen every day when the hazard is
well known (chain saws, lawn mowers, chippers, etc., etc).

Warnings of obvious things ("coffee is hot, be careful") would probably
not change behavior. Warnings of some subtleties ("This coffee is much
hotter than usual so it will stay warm through your commute. Thus, you
can be much more severely injured than you expect if you spill it. Be
careful.) would I believe change behavior.

However, it may cause people to not buy the coffee in the first place.
That's not what McDonalds would want. Typically, those who are forced
to put warnings on things want them to be as dull-sounding as possible,
so that they are disregarded, and don't affect the bottom line.

Jose
--
Humans are pack animals. Above all things, they have a deep need to
follow something, be it a leader, a creed, or a mob. Whosoever fully
understands this holds the world in his hands.
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