It doesn’t seem like it based on these responses where some posters have stated they’d turn up to a wedding empty handed! I wouldn’t do that even of going to someone’s house for a meal one evening. Personally, for acquaintances at a wedding I’d put £100 in a card, £300 for a close friend and quite a lot more for a sibling.
At my own wedding we paid for the hotel overnight for all guests and had a free bar. I paid some of my friend’s travel expenses also as I just wanted them to be able to be there. We did not want random stuff as I really hate clutter and we had what we needed already. However, most people would feel terrible attending a wedding and giving no gift at all, it’s just rude. It’s perfectly normal for a couple to want to make clear that people don’t feel they have to give a present if they are struggling with money. We did similar. The wording is being described as “twee” (presence not presents) but I’m yet to see anybody suggest a wording they’d find acceptable instead if they object to this?
As I noted earlier in the thread, perhaps the sister has some friends that she knows are struggling financially and wants them to be able to come without feeling awkward about being unable to observe the usual etiquette to give a wedding gift. It seems clear that the wording on the invitation is designed to remove any awkwardness in such situations. How would you prefer it to be phrased? Nobody has answered this.
I doubt this comment on the invitation was aimed at her own sibling because surely noone would go to a sibling’s wedding and not give even a small gift?! Unless they were totally destitute, in which case the sibling would already know this and it wouldn’t even need to be discussed and certainly wouldn’t be communicated about via a general invitation sent to all guests.
People’s means are different and most people do want to observe the social etiquette that exists across almost the entire globe that wedding guests give the couple a gift so despite the OP’s sister wanting to make it clear it isn’t necessary in order to come (kind of her if she perhaps has friends struggling with money) she also seems to want to ensure that those who would never dream of turning up empty-handed don’t waste their money on “thoughtful” gifts that are not wanted or needed. The message is, therefore, perfectly sensible and reasonable and not remotely unusual based on weddings I’ve attended over the last 20 years: no need for a present but if (like most people) you want to give something, money is best as it will actually go on something nice/ useful.
Multiple posts have stated that if you write nothing on the invitation about gifts you are bombarded with enquiries about what to give because people generally want to do so. Most people prefer clear information as they want to give something that couple would like, that’s kind of the whole point of it.
The people objecting to this seem to be either people who have weird issues about giving money as a present - which is a very British cultural hangup as it’s very normal in most countries and is something that most young British people have also now left behind - or people who are in a strop because they feel going to a wedding is an imposition because they have to wear appropriate clothes, perhaps get babysitters, pay travel expenses etc, like for any other event one attends. The latter group seem to be people who are the perpetual moaner type and would find something to complain about in just about any situation or actually dislike their own family/ friends so resent being invited to a celebration, so don’t appear to like their family and friends much to start with. For someone to be moaning about this when the bride is their own sister is totally weird. Who would even contemplate not giving their own sister a wedding gift, even if it was only a tenner in a card?
As many posters have noted, to start such a thread or even bat an eyelid at this comment on a wedding invitation from a sibling, rather than talking to them about it if there is any “confusion”, seems to indicate that the OP dislikes/ resents her sister, rather than this genuinely being an issue about wedding presents, which really aren’t that complicated.