What's the difference between rewarding a service that goes above & beyond pre-paid expectations "vs" buying someones loyalty through Tips (for as long as you're physically present)?
I don't understand the intent of your question.
"....rewarding a service that goes above & beyond
pre-paid expectations ..."
Most outfitters, with exceptions, ask for payment be made in full prior to the start of a clients hunt/safari/activity.
I don't tip until services have been rendered.
"...buying someone's loyalty through Tips (for as long as you're physically present)"?
Again, I don’t tip until I'm ready to depart and my tip, if any, is based on the services I did or didn't receive while physically present.
The only exception to tipping during a trip would be tipping temporary PH, tracker, skinner(s), others who have assisted in the hunt and/or recovery of my animal(s) while at a different concession.
As for transferring extra funds for the trip to an outfitter.
I have transferred extra/additional funds to an outfitter for my use during the trip so I wouldn’t have an excessive amount of cash on me while enroute. But this has only been done using outfitters I have previously used and trust.
I wouldn't advise nor advocate for anyone to send excess funds to an outfitter they have no personal experience or lengthy relationship with.