I am definitely not saying it is not appropriate to express your gratuity to the CSR, or any other casino employee. And, the only time I've ever had a W2G, I did tip a reasonable amount for my $1221.00.
I was offering my opinion, and observations, about why some AP's (and poker "pros") do not or may not tip. Having been in the biz, I used to feel the need to over tip as an example to others. I've had a true reversal in my thinking about the topic.
Yet, when asked "What is an appropriate tip?" (at the poker table), my answer is usually something to the effect of.....
"That is entirely up to you. Some generous people may give up to 10%. Thrifty players may give nothing. Generally for a nice pot, the equivalent of the ante or the blind bet is about average. It is totally up to you."