Sherlock Holmes: A Game of Shadows (2011)

Factual error: In the scene straight after the opening credits we are taken to Baker Street where construction work is being done. This work is identified by a sign with a logo as being for the underground line. The logo type face was developed by a Mr. Edward Johnston for London Underground from 1913 but the distinctive typeface used in the film was not in place until 1919. This is obviously long after the 1891 setting of the film.

Sherlock Holmes: Uh, hmm... Right. Where are the wagons?
Madam Simza Heron: The wagon is too slow. Can't you ride?
Dr. John Watson: It's not that he can't ride... How is it you put it, Holmes?
Sherlock Holmes: They're dangerous at both ends and... Crafty in the middle. Why would I want anything with a mind of its own bobbing about between my legs?

Trivia: The final chess match between Moriarty and Holmes is based loosely on a famous chess match between chess masters Bent Larsen and Tigran Petrosian. The match involved the sacrifice of a queen and a surprise checkmate, thus mirroring Holmes' apparent sacrifice of himself to stop Moriarty.

Question: How was Sherlock and his home team able to just take Moriarty's fortune at the end? What exactly were the grounds established justifying taking all of his stuff?