i think you have put it very well there, hatwoman.
aitch, i don't think charity = bad form in a vulgar, declasse way... and i think for a 50th wedding anniversary for e.g. it is a good idea.
but i do think it has to be handled carefully to avoid a whiff of holier-than-thou (pace littlelapin who obviously handled the whole matter perfectly ).
the only time we have ever had this, it really was worded along the lines, "unlike those other money grubbing couples and their horrid vulgar wedding lists we, being so much better than other people, and much, much cooler to boot, want you to make a donation to charidee..."
there was a try-hard wannabe "ironic" tone to it all.
and no we didn't go before everyone gets all up in arms about that - they were acquaintances rather than friends.
plus i think there is quite a deeply ingrained traditional view that the guests help the couple "set sail" as hatwoman put it so well - and guests feel denied that in a way if cash or donations are "encouraged".
so my reaction to solicitations for donations to charity is very much coloured by my own experience - of course.