It's been discussed before. It's inevitable. Vancouver isn't a big city.
The etiquette is "do not approach". At the most, smile or a brief nod.
Like ourselves, their professional world and their private lives should not intersect.
Sure you can talk about it in your private time together but out in public, not so much.
Think about if you were with your girlfriend or wife or mom, and they come up to you while you were having lunch with your kids, kiss you on the cheek and tell you loudly that they can't wait for you to bang their brains out again, and don't forget about her new rates.