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>>>but vhg, it's fun to bait them
For people who are technically aware it may be fun to bait them.
For any elderly person (or even young person) who does not quite understand how these computers work it may be they think it is a genuine call.
I have seen and read of many people who have been conned out of hundreds of pounds by these people.
My update is aimed at non-technical people, not people who know the difference between a Windows PC, a Mac, and Linux, I assume they will know these calls are a con.