If you consider yourself a pro, don't do this. No matter how justified you might be, you never know when someone in the crowd or someone you're playing with might be looking for a bass player down the line, and sabotaging the gig would likely reflect really badly on you.
100% agree with both of these.Go in and be as good of a player as you can be, and an up front businessman who delivers the goods. Be reliable, be nice, be as musical as the situation allows. Kinda like you've crossed paths with this guy, you never know who you'll cross paths with down the line. Play and work to found a good working relationship with the keyboard player. Basically, take the high road here, and start building a reputation.