Well, it had to happen. Pi's imam, priest, and pandit notice he's going to mosque, church, and temple.
All this comes to a head when Pi and his family are out enjoying each other's company and these three religious leaders happen upon them. They're shocked that Pi knows each of them.
There are some insults. Some disagreement. But everyone comes basically to the same conclusion: Pi has to choose one religion. Of course, Pi doesn't think so: "Bapu Gandhi said, 'All religions are true" (1.23.54).
Pi's father defuses the situation and the family has a good laugh. Oh, Pi. They eat ice cream sandwiches.