When someone takes liberties, doing things too boldly, you can describe them with the adjective presumptuous.
Presumptuous comes from the Latin verb praesumere which means to take for granted. It means taking for granted your access to someone or power to do something. It's a very satisfying word and effective word because it belittles someone at the same time as criticizing him. In Shakespeare's "Henry VI," Northumberland calls Warwick "presumptuous and proud" for trying to get rid of the king. It's usually pronounced with all four syllables, pre-ZUMP-choo-us, although pre-ZUMP-chus is acceptable as well.