Lyft Pioneer credits are meant to give new passengers a chance to explore the platform, and get them to know the broader driver community, not for giving rides to people you already know. Lyft rides should be organically matched up by our system, and not pre-arranged by other means.
A good rule of thumb is to ask yourself if this is a ride that you would be giving to that person even if you weren't a Lyft driver (for example, taking a neighbor to the grocery store or dropping someone off at soccer practice). If the answer is yes, they shouldn't be using Pioneer credits to pay for that ride.
Finally, you should never stop and start rides to ensure that they stay under the Pioneer amount. If a ride is going to be over the allotted amount it's up to the passenger to pay for the difference.