What I've heard is that the police have a job to arrest the suspects because that's how they get promoted, so they'll try their best to catch you lacking.

In this situation it's always beneficial to have an experienced individual who knows the ways around and who can guide you and let you know about your rights and what to do in the situation.

Obviously, there's no need to appoint a lawyer if you have really straightforward information and are innocent.

However if there are any complications from your side, it's always better to appoint a lawyer to know what you can and what you shouldn't say.

You don't have anything to gain with a lawyer, but there certainly is a very high risk without a lawyer.