Miss Manners: Do you give a baby shower present to someone who didn’t acknowledge your wedding gift?

DEAR MISS MANNERS: I am at the age where many of my friends’ children are marrying. I am always delighted to be invited to celebrate with the happy couples, and pleased to give a wedding gift to start them out in life.
Alas, I very rarely receive an acknowledgment of my gifts. This seems to be accepted behavior.
What should I do when the invitation to give a gift for the impending baby arrives? My baser self would very much like to snarl that they have a lot of nerve sticking their hands out again, but I value my friendships with their parents.
So far, I have taken a deep breath, sent a gift and talked about them behind their backs — like decent people do.
Does Miss Manners have a suggestion for a polite way of indicating that, since they couldn’t be bothered to acknowledge the first gift, subsequent gifts should not be solicited?
GENTLE READER: Decent people do not, as you said, admonish people directly. Nor do they go looking for trouble. If the impending babies do indeed materialize, Miss Manners suggests you politely decline the invitation — both to attend any festivities and to provide a present.
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(Please send your questions to Miss Manners at her website, www.missmanners.com; to her email, [email protected]; or through postal mail to Miss Manners, Andrews McMeel Syndication, 1130 Walnut St., Kansas City, MO 64106.)