score:2
I note that Peter the Great was very tall - 6 feet 8 inches - and so unlikely to be mistaken for some random stranger.
There are many stories about important people being mistaken for less important people.
For example, in one story Joseph II, Emperor of the Romans 1765-1790, was travelling incognito, possibly in France, and was asked to be a witness at a baptism. And he filled out the spaces in the baptismal registration form. Personal name "Joseph", surname "The Second", occupation "Emperor".
William T. Sherman was the commanding general of the United States Army from 1869 to 1883. He usually made his headquarters in St. Louis instead of Washington, DC, and made many inspection trip in the west. Sherman usually dressed very shabbily. According to one story, Sherman saw a soldier brutally beating a mule and told him to stop. The soldier kept on beating the mule. Sherman asked if the soldier knew who he was. The soldier said something like "Don't try that with me. Every bum claims he's General Sherman."
Upvote:4
The anecdote contains an anachronism. It alludes to two major events of Peter's reign separated by more twenty years, his supposedly incognito Grand Embassy (1697-8) and his Table of Ranks (1722). Taking this story at face value, the episode could have occurred at the very end of Peter's life after the new ranks were well-known.
Perhaps, but I'd wager that Peter did not get lost on any incognito countryside walks in his old age.