It appears as though you have dysfunctional entitlement issues.
When you invite someone as a GUEST, you are the HOST (in your case, also the Bride and Groom). Regardless where your reception it is located or if the Bride and Groom willingly spend the cost of a car for their 240 minute reception, your guests are not obligated to bring a gift and it is very tacky to ask people to bring "something". Whenever someone is invited to a wedding, um, yes, the food is FREE. DUH.
Unless you want to sell tickets to your wedding, yes, it is FREE to your guests. If you selected expensive food and music, then that is YOUR CHOICE. A guest does not have to come up with an admission fee via a gift. Wedding gifts are not mandatory, they are completely optional.
I had a friend insist that everyone bring an "envelope" (in other words, money) as a gift to her wedding. I was so sick and tired of hearing her tell everyone that she wanted "envelopes" instead of gifts that I did just that. I ordered a set of gold paper lined Crane Stationery envelopes for her wedding gift. LOL.
It is so low class to beg for gifts, no matter how big or small they may be. You are not entitled to a gift and asking for them just makes a total fool of yourself, with a huge dose of embarrassment.
EDIT: in your "update" you state that you are not demanding, but you are asking for gifts. Noooo, you said, at first, that you were "telling guests they have to bring a gift..."
That is not asking, that is, in fact, demanding. On second thought, I doubt people who live under a bridge can even afford a $25K wedding.