Jason knew he couldn’t just confront anyone based on a hunch, especially with something as flimsy as attire or a suspicious glance. Calling people out as thieves without solid proof would be reckless and could backfire, alerting the real criminals and putting himself and others in unnecessary danger.
The thought weighed heavily on him. If this gang was truly operating on board, any sign that they were being watched might push them to desperate measures, endangering the passengers and crew on board.