I made up the last one. We Chinese don't use the word "institution" in this sense. We say "the big issue of marriage", which is probably the closest to "institution" as I see it. My response is to recommend American actress Mae West's famous quote: "Marriage is a great institution, but I'm not ready for an institution yet."
The word "issue" works when the quote is rendered in Chinese, and could go something like this: "Marriage is a big issue. I'm not ready for the big issue. I'd better off focusing on the trivialities instead."
As a matter of fact, Chinese netizens have distilled their collective wisdom into a comic strip. It uses the strategy of preemption.
Before your relative opens her mouth, you fire off a volley of questions: "Auntie, how are you? Has your daughter started dating? Have you bought a wedding apartment for your son? Do they own a car now? Did you make money from the stock market last year? How much is your pension? How does your kid perform in school? Hey, have you stopped going to the square dance? You seem to be gaining weight. Bye now, auntie."
Call it "Do to others what they will do to you". Let them have a taste of prying into others' personal affairs. I'm sure the stock market question will kill whatever interest they have in you. Their answers could drag on for hours, or they may weep and flee in humiliation.
Honestly, this strategy can work only with people who don't have close blood ties with you. But I have yet to see a ruse that can shut up a parent or grandparent. And the reason could be: You care about them and you know they care about you. And it is the way they show their care that makes you uncomfortable. This is part of the generation gap.
So, many on their trip home resort to procrastination as a kind of placebo. "Oh, I'm dating someone, but (s)he cannot be here because (s)he has to visit his or her parents." Then will come the coercion to produce a photo as evidence.