Well it depends, if I ever lift someone it would go something like this:

*I slow down and evaluate whether this person would be acceptable to lift...
*Then check that I don't have someone special in the car with me (just in case something bad happen)
*I stop and offer a lift...
*Make sure my shotgun is loaded and pointing at them...
*Make sure my mirror is always looking at this hiker, so when he/she makes any sudden movements...

Sometimes I might just take my great dane with and he'll be backup when the shotgun jams.