Great discussion. I'm chiming in late, but my $0.02.
"No thank you. Maybe later." means you have some reason not to dance this
particular dance with this person, but would be open to future offers.
"No thank you." with a friendly smile is similar but less explicit.
The above should cover 99% of the cases!
"No thank you." without a smile and turning away immediately, is a vague
way of saying, "Please don't ask again." Some people will get the
message. Many won't because the "thank you" diffuses the message.
"No" without a smile and with an immediate turn may be more effective, but
is still vague.
"No. Please don't ask again." is a kind and polite response when you have a
reason never to dance with a person. It tells the person where they stand,
and avoids expectations that might lead to future invitations.
Even kinder is, "No, I don't feel (safe|comfortable|whatever) dancing with
you." It lets the person know unambiguously that there is a problem and
indicates that you might be willing to elaborate.
This leaves open the possibility that the person might ask questions and
learn.
Unfortunately, it also leaves open the possibility that the person will ask
questions as another way to force unwanted attention on you.
In my intro lessons I say something like:
"Feel free to ask anyone to dance.
You will find that most experienced dancers will be pleased to dance with
you.
However, if someone turns down your request, don't be offended. There are
many reasons why they may not be available right now.
If someone you don't know invites you to dance, be open to the idea that
you may be about to make a new friend.
However, you should also feel free to decline to dance with or without
explaining if you need a rest, or have a partner for the next dance, or if
you aren't comfortable dancing with the person who asked."
Although I have occasionally heard of the "rule" that started this thread,
I don't feel that people should ever be penalized for declining an offer to
dance.
Dale
--
There are only two hard things in computer science: cache invalidation,
naming things, and off-by-one errors.