A card with money inside is the norm...They also have now like a chest for the cards, or a wishing well.
So said card-gift(money) are placed into the ''well or chest''.
So take a card, place a token offering ($50-$100) is the norm.
If you don't want them to know you have given it, just write ''from a dear friend'' or ''dear family member''.(some people even get someone else to write the card....so they don't know who it is.
Gone are the days now of gifts.
People were given too many of the same thing.
The bridal register...also was becoming a pain, with brides really forcing people to spend too much....or placing them in a corner.
(The bride or couple would choose what they wanted from say a department store.Then one would view what others had bought, and you were more than likely forced to buy the big items, as all the middle of the road were gone!)
So the card and money are best.
P.S. If there is No where for the card, and they really did not get the chest or wishing well, you have two choices.
1.Slip it to one of the parents and ask them to give it to them.
2.Just take it home again with you....if you Really are sure, no gift of Any type is wanted.Just 'suss it out when you get there''.
But, at least you went prepared.That is an absolute must, for a wedding!
Most weddings I have been to lately use wishing wells. You give couple money and place it in an envelope. Wish it had been around when I got married. That way you can buy something you really want or need. With so many people living together these days, the couple has most things they need. The money from the wishing well then goes towards a honeymoon or a deposit on a house.
If someone asks you not to bring gifts then it seems stupid and inconsiderate to do so. You have been given a specific request, and there will be a reason for it. Why spend money on gifts people don't want? It also seems rather unfair on the other guests who don't brings gifts, who might then feel awkward.