Let's think for a second about the fates of the real-life people Davie meets on his journey through Scotland: Cluny Macpherson, dead in France; James Stewart, hanged for the murder of Colin Roy; and Robin Oig, hanged for the forced marriage of Jean Kay (source). In a lesser novel, the life of the Highland outlaw might be glamorized or romanticized. But in Kidnapped, most of the clansmen Davie meets are outcasts, constantly on the run from British soldiers or rival families. Stevenson is not overly sentimental about this Highland history – these outlaws are more often than not unfriendly and unwelcoming toward Davie, for example. But, as the final remnants of a Highland clan tradition that has to go into hiding, they can't help but be tragic figures.
Stevenson's references to the anti-Tartan dress codes of post-Culloden Moor Scotland emphasize the transitional period in which the novel is set. Earlier forms of clan rule are being forced to give way to English authority.
The Highlanders continue to collect weapons, refuse to wear Lowland clothes, and send money to their exiled clan chiefs in gestures of defiance against English rule.