Here's a pro tip.
Whether your trap works or not is entirely contingent on the amount of hp the opponent has, not the strength of the trap.
In other words, if the pet you're trying to catch has 34% health, it will be nearly impossible to catch.
If it has 2% health, you'll trap it on the first try.
Like everything else with pet battles, it's not working as intended, and it's buggy.