We have a no-kissing rule also. We feel there can be more of an emotional element.Kissing on greeting is fine.Kissing has happened in the heat of the moment and that's fine we don't beat ourselves up for it..it just happens sometimes.
As to kissing in fourplay leading up to sex
we don't have an interest maybe odd ,but never occurs to us it's not an important part of swinging to us.To us kissing is a more intimate form from our point of view.Yes sex is intimate also,but for us sex is more lustfully driven,where kissing
to us is more intimate and we prefer to share that with ourselves.
The reason we feel it is more intimate is when kissing your eyes are usually closed ..if not it would be well yuck.LOL,and for that brief time your whole focus is on that one person,and that is something we are not interested in and we prefer to keep the kissing to ourselves, as it has more meaning then sex does.
We haven't had much problem or been slammed for it..to each his/her own some enjoy it and that's great it's just our policy not to.It is been our experience that quite a few couples we met have the same rule,those that differ felt it was odd,but respected the rule,and those who turned down because we didn't that's fine to ,all boils
down to incompatibility,everyone tastes and views of fun are different.
That's just our opinion.