Yes, the community is very creative. That particular blog article is from 2015. Since then, other community members have made a number of methods with additional features and enhancements.
In particular, one of the most popular right now is a virtual presence sensor which has an on/off switch. If you notice, in the blog article, the author has a virtual presence sensor which will always show as present, used for when a relative was visiting.
With the newer virtual presence sensor that is also a switch you can do all of the same things in the blog article, but you can also turn it off, for example if you all go out to dinner. This allows your regular “away” routines to run when the house is empty. 
Of course, having that device doesn’t obviate the original use case in this thread, which is not just about marking the guest as present, but actually having a different “guest” mode so that routines might run differently. For example, if a guest is visiting you might not want to have your normal “night” routine set off a siren if there is motion in the downstairs hallway. 
So both options are useful- – guest mode and virtual presence sensors.