As positively as possible of course as you don’t want to come off as complaining – ONLY if they bring up the topic.
Sample situation:
pax says: “I bet you make A LOT of $$”
me: I reply w/ a smile saying “that USED to be the case but these days its the tips that help”
pax: “I thought tips were included automically”
then I go on explain from there by using that statement as a “segue” (means smooth transition)
That’s how you do it. Just NEVER bring it up.