Re: No boxed gifts please
donate the gifts to charity or store them in my parents or inlaws basement until the time that i can actually use them. i stored ALL of the gifts i got because we were living in a very small 1 bedroom then and had no room. 4 years later we’re in a much bigger home with a proper kitchen and i’ve unpacked them all and am using them. there is no expiry date on these things, you know? they can be used, its just that you don’t want to cart them across the country just now, right? it doesn’t mean the gifts were unwelcome or that i was peeved i received them. that’s my issue with this wording- it makes the couple seem ungrateful too and it puts pressure on the guests to shop either at a specific store or to only bring money. not every family can afford to gift a decent amount and showing up with $50 might be embarassing for them. as you mentioned, possibly a separate insert card is a solution although, that, too, seems a bit forceful. ideally word of mouth is how information about wedding registries is spread if people ask what to get the couple. and if your guests care, then they’ll automatically bring cash without needing a reminder, no? 
they’ll know you’re in transition and respect that.