If the going rate is $5000 and your guide charged $2500 and did a great job, then by all means be prepared for a tip. If your guide demanded a premium and charged $7000 for the same hunt, but you bit it off because of the reputation, then I would have a much tighter grip on my wallet.
The thing is, lots of times the cost of the hunt is going to the outfitter (not the guide), be it $7,000, $2,500, or whatever. Sometimes the guide and the outfitter are one and the same, but often they're not. When the guide is working for the outfitter, he's depending on tips because the fee for the hunt is not his to keep, set, or negotiate.
