As a caddie, I tend to steer away from clubbing players because most won't admit their true average distance. I had 2 players argue with me about yardages on the range pre-round, then I lasered them, and they still said it was wrong because "I hit my 6-iron farther than that." So, in this case the flag was 177y, and if they get on the course and I say it's a 5-hybrid, and they ask the yardage and I say 177, they will be very angry.
Also, I made the mistake of reading a chip for a guy who asked that I not read putts or chips. Totally my fault. It was the 13th hole, and I slipped up. He was visibly upset, but chipped it to tap-in. He asked me to read putts and chips the rest of the round. I'm not saying I was right, I was wrong to do that, but I didn't do it on purpose, and I think he realized we could help each other. Additionally, he was a member of the opposing club in an interclub match, so I don't know if they think we might give the members any bias. Maybe that factored into his thinking.
I'd be interested to hear from other caddies, but at our club the majority of the caddies are around scratch or better, or have played in HS, college, etc. Is that similar in most caddyshacks? The guys I caddie for are genuinely blown away when they ask my handicap.