I would think virtually every PPL holder, has taken up friends and family, then given them a go at the controls. Nothing wrong with that, not illegal,
In Canada doing so would not be legal...
The definitions:
A person is either a:
"flight crew member" - means a crew member assigned to act as pilot or flight engineer of an aircraft during flight time
or a:
"passenger" - means a person, other than a crew member, who is carried on board an aircraft;
(no middle ground on that)
Then...
401.03(1) Subject to subsection (2), no person shall act as a flight crew member or exercise the privileges of a flight crew permit, licence or rating unless
(a) the person holds the appropriate permit, licence or rating;
(b) the permit, licence or rating is valid;
(c) the person holds the appropriate medical certificate; and
(d) the person can produce the permit, licence or rating, and the certificate, when exercising those privileges .
Some time ago I was read the riot act by a Transport Canada inspector for letting my buddy fly the 182RG he owned (and worse 'cause I let him fly left seat) after he had his medical suspended. TC and I agreed to disagree, 'cause there was no way they could prove their accusation, but I got the warning....
The person with the license flies the plane
Now I'm not saying that I abide by that regulation all the time, but it is written....