I agree, call it a vow renewal or a wedding blessing, rather than a wedding. If having a gathering afterwards, call it a party, not a reception. That alone will signal to most people that gifts are not required (and of course don;t register). Some people will still ask what you'd like as a gift; you can out the word out via family that no gifts are expected. If you want, a favourite charity can be mentioned. If you do get people who bring gifts to the party, accept them graciously- you can re-gift, or give them to charity. Any checks should be cashed, as it is rude to snub a guest's gracious gesture by not doing so, but you can give the money to charity.