The bonus trap, defined
A bonus trap is a genuine bonus whose terms make conversion to cash practically impossible. Note what that isn’t: it isn’t a fake offer or a non-existent casino. The credit really appears. You really can play with it. The trap lives entirely in the conditions attached — the playthrough you must complete, the caps on what you can keep, the clauses that void everything if you step wrong.
That’s what makes it effective. There’s nothing to “catch” in the headline, because the headline is honest: “100% up to £100”, “50 free spins”, “£200 welcome package”. The bait is the number you see; the trap is the page of terms you don’t read. By the time the terms matter — at withdrawal — the deposit has long since been made, which was the point.
Crucially, a bonus trap is not always a question of dishonesty. The terms are usually disclosed somewhere. The trap is the gap between how an offer is marketed and how it actually works — and that gap is wide enough that even players who read carefully can be caught.