Factual error: During the opening credits, Fernand Mondego is tipping back a bottle of booze on the rowboat. The bottle is quite out of place for 1814, as it shows modern "makers marks" on the bottom. Glass bottles during the French Revolution would not have had these markings; they did not start appearing on glass bottles before the middle of the 19Th century. (00:01:45)
Factual error: The imprisoned Count is crawling through a tunnel with his neighbour prisoner leading the way. His neighbour prisoner has a lit candle showing the way, but when he breathes out, the candle goes out but the 'light' remains. You can clearly see smoke rising from the candle before the scene cuts away. (00:43:25)
Factual error: When Edmund Dantes is promoted to Captain, we clearly see a brass diving helmet on a shelf in the office. Augustus Siebe's hard hat diving dress wasn't invented until 1819, and didn't appear as in the movie until at least 1837.
Factual error: Napoleon continually addresses the British officer on Elba as 'Lieutenant' Graypool despite his displayed sergeant's stripes. Napoleon is a professional soldier who has fought the British and lived with them for some time - he is unlikely to be confused by British rank insignia.
Answer: I believe it's just because there is a dirty smelly man that she doesn't recognise visiting her ailing grandfather, she just wants to keep an eye on things.