There's likely deposit scams everywhere. And there are other reasons you might be adverse to paying a deposit (e.g. privacy). But Tryst has a decent reputation. They seem to do a good job vetting providers that post ads. I'd say 90% of the Ottawa providers on Tryst are well known, with good reputations. Some ads are out of date (e.g. provider announced retirement but ad remains). You are more likely to get helpful feedback if you make a new post asking for info about the specific provider on Tryst you're interested in who is asking for a deposit.
