Fair point RE: mobile and mouse, sicne there's no pointer.
Facebook tracking cursor, mouse. [webmasterworld.com]
The linked article does mention that mobile isn't an option there, but the visibility of elements of the page is somewhat comparable, I guess since there's more scrolling and less screen estate available.
In general, it's quite safe to say that a bot could easily appear human, at least for an amount of time. The most important way to detect is how they are using the site, i.e. repetitious behaviour, to achieve whatever goal it has.