when dd was younger it pained me to see all those gifts come in, it felt like a tremendous waste.  but in the end, like you, it would have caused a stir and commotion.  what we did do though was limit the number of guests to her age plus one.

gifts are tough.  perhaps i'm old fashioned but putting on the invite "cash" feels a little vulgar to me.  i think most people understand what a couple wants or if not, can ask...at that point "cash" would be a perfectly acceptable response imo.

i like gift giving and making sure the gift i give is well rec'vd. if i don't know what to give i do a little snooping around with the family and friends. it isn't a transaction afterall...it's a gift.  but that doesn't mean i don't give cash if that is what is desired.