Did highlanders 'trouserize' their kilts during the bans?

[Allan Thomson]

The picture of the Mcdonald Brothers one wearing trews the other a phillabeg was painted during the period when Highland Dress was still proscribed.

I'm pretty sure there's other images of Highland clothing painted as part of a portrait before the 1782 repealment of the act.

Perhaps if it was the belted plaid that was banned but not other forms of Highland Dress as the richer members of society could afford tailored clothes whereas the poorer members could not?