reckon without one's host

Etymology:

• Originally stronger, metaphorical form of to reckon without or not reckon with something or somebody, not in literal sense of planning without or ignoring something or somebody that is essential or whose input or assent is essential, i.e. originally only in metaphorical, not literal reference to a person who estimates the bill in an inn instead of or before asking for it from the host — despite claims to the contrary in the Chambers's Twentieth Century Dictionary and the 1913 edition of Webster’s Dictionary.