Miss Manners: Is it rude to ask someone alone with a laptop at a coffeeshop to share the table?

DEAR MISS MANNERS: Is it rude to ask someone alone with a laptop at a coffeeshop to share the table?

GENTLE READER: On the contrary: It seems like pretty good assurance that neither of you will have to make small talk.

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DEAR MISS MANNERS: I have embraced a hobby that is seeing a resurgence amongst young people: knitting. But I’m concerned it may be impolite to knit in the presence of others.

For instance, is knitting while riding on a train with a companion acceptable? How about while visiting intimates’ homes, while they are engaged in their own activities -- such as cooking, but still chatting?

How about knitting in a public place, such as a coffeeshop? When an acquaintance approaches, may I resume knitting after a warm greeting?

Although knitting is a rather mindless activ