Factual error: Diamonds, being pure carbon, would burn in the cremation of the body containing them. Cremation temperature is about 1,000 degrees Celsius, diamonds burn at about 850.
Revealing mistake: When Bond hoists Mr. Wint overboard with the bomb tied to his coat-tails, Mr. Wint is not Bruce Glover but a stunt double.
Continuity mistake: Tiffany is wearing a red and purple bikini top cover on the oil rig. But in the last oil rig scene where she shoots the machine gun from the tread of the crane and falls off the rig, her top changes color to brown and red. No purple at all.
Answer: If you mean by hiding - why is he never seen normally - then it's because he is a recluse and doesn't like to be seen in public (like Howard Hughes was). If you mean by hiding - why was he not seen during the movie - then it's because he was being held captive by Blofeld and his minions. Spectre didn't want him out and about ruining their plans.
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