Pax, if you have a pre-Vatican 2 book of theology, you can look this up for yourself. It's right there in Jone, if you have that.

Applying pre-V2 rules to V2.
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Someone attending a funeral or wedding is not actively participating in the false worship.
A protestant wedding doesn't have "false worship". It's a saturday wedding; it's a natural law good act. Quit comparing a Sunday protestant service to a protestant wedding.
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He is merely being present at an important occasion, and shows his lack of acknowledgment of the false worship by refusing to participate in it.

If you truly want to show a "lack of acknowledgement" then you don't show up. "I'm going to cancel plans to attend a wedding, dress up in a suit, drive to a church...all to "not acknowledge" something."

This isn't exactly a new question that no one ever heard of. This is the universal teaching before Vatican 2.
It is a new question, because saturday protestant weddings didn't have fake masses.