In their long history both Marriott and Hilton floated a policy of "spouse stays free", later evolving to also include children of certain ages. This was a face-saving measure to work around hotels that charged more per person - especially prevalent at properties that included breakfast and was designed to encourage family stays. As societal norms have changed these policies are certainly not emphasized any longer, if they even still exist. As others have noted, hotels in Europe and Asia often flex the rates for more than one person and I recently encountered a domestic Courtyard that was essentially charging an additional $8 for the $10 daily credit for my wife. That said, the OP example of $60 does sound like the result of another parameter such as rate increase. As a sidebar note, where an extra person can really be problematic is in room searches, again mostly in Europe and Asia, where room size or number of beds is an issue. (See the "Phantom Child" issue among others.)