I don't have a problem with wedding lists or requests for cash for specific purposes. I think they're very useful if you want to buy the couple a gift, but you're stuck for ideas and would like to get them something they need. However, I usually give them something non-list related anyway, and if they don't appreciate it, then stuff them!
Nor do I have problems with giving gifts for second weddings.
What I do have a problem with is the way that its sometimes worded, or the implication from the couple that its expected.
With the wording, I would expect it to say something along the lines of 'if guests wish to give presents, gift ideas can be found on our gift list at blah blah... ' Anything saying 'the bride and groom would appreciate cash donations for so-and-so', without also including a 'no gifts expected' sort of line, is kind of rude.
I think a lot of folks don't think about their wording hard enough, because it can offend and they may not realise that its being interpreted as an instruction.
We had a bit of a wobbly time recently concerning the wedding of some quite close friends. The bride didnt just imply, but stated quite clearly that she expected presents.
She said that as they were forking out such a lot of money on a party for so many people, that gifts were a small token in exchange, and that it would be rude not to give them.
We (some of the friends of bride) were quite gobsmacked at this attitude. Our (my) opinion is that the wedding is for you (as the bride and groom) and its your choice to celebrate it in the way you wish, but to imply its for the benefit of others is downright cheeky.
Although people love weddings, they usually have to fork out a fortune just to attend and they're not doing you a 'favour' in doing so, they're sharing your special day as you presumably want them to be there with you. The idea that it should be an 'exchange' is just insulting to those people.
Sorry, had a bit of a ramble there...Anyway, we agreed to disagree and they had a lovely day...