For the day guest invites we would like to ask for cash if anyone wanted to give anything. We would put it towards some sort of honeymoon - we pretty much decided we would go all out on food/drink for our guests so everyone has a great time so no budget for honeymoon. Would it seem less grabby to just simply have - if anyone wishes to give a gift, please could we have a contribution for our honeymoon. I hate the whole poem thing many of them are too long winded for me. It makes me uncomfortable the whole thing really! I know our family will want to give something, so I would rather give direction or we would probably end up with 50 interesting ornaments for our flat!
We just had no list and most people then have us money anyway but it was a choice and not asked for. We also got some gifts so maybe not an option if you really just want cash but I felt it was rude to specify and didn’t want to miss out on thoughtful gifts (like a handmade photo album)
I honestly don't mind a polite 'no gifts necessary but if you insist cash for honeymoon/house would b lovely' messages but if you think there's a risk anyone would take it in the wrong spirit do as suggested above and say nothing. 99% of people won't come empty handed and 85% of them will give a cheque. The other 15% will give a gift of their choosing (something traditionally gift listy) but that's lovely too.
I don't think it's rude to ask for cash at all but my DM disagreed, so we've gone down the route of putting nothing on the invites at all. That way people can give, or not give, whatever they feel comfortable with. A few people have asked and we just say that a bit of spending money for the honeymoon would be lovely, but we don't need gifts so it's entirely up to them.
Personally I think what you've suggested is fine, I've read similar in wedding invites and have never ever thought it was grabby. Usually I'm relieved because it's an easy present that I know the couple are going to appreciate and make good use of.
If I've seen something that I know the couple would particularly like I just get it for them anyway, regardless of the fact that they've asked for cash instead. Ditto if they've put together a wedding list and I've seen something that's not on it but I know they'd love.
We had a list when we got married, some people bought from the list, some people gave us presents not on the list, some people gave vouchers or cash and some people gave a card and no git. All lovely and totally appreciated.