Inhumane and unnecessary. Use a pinch of fishfood daily (just as you would for a damsel) and the tank will cycle. Stop the fishfood a day after you see ammonia spike, and when you're ammonia-free, you're cycled.
It's not the fish that cycles the tanks, you may tell them from me, it's feeding it. It's only if the fish DIES that it cycles the tank, and that's completely unnnecessary.
If that is a sample of their expertise, do not believe them about substrate, skimmers, filters (unneeded) and medications, among others, and I would not trust them on a proper tank, either. That advice is from the 1980's and prior.