Paraphrasing the rules for legal trials from GURPS:

A trial is a contest of Law skills between the prosecution and the defence. Most people will hire a lawyer and make use of their Law skill. Do you really want to defend yourself and use Law at the default skill level?

Importantly, evidence is only a modifier to the skill rolls, not the determiner of the outcome. This is actually a really good argument for convincing a roleplayer that they should hire a lawyer.

Transcript

{establishing shot of Rebel fleet}
GM: Meanwhile, back at the Rebellion...
Admiral Ackbar: Now that that's settled, and I have a captive audience, we can brief you on some recent intel.
Lando: Well, look at you. Exonerated, huh?
Han: Yeah, someone must have told them about my little manoeuvre to save the Rebellion.
Chewbacca: That would have been me.
Lando: Yeah. Good call letting Chewbacca handle your defence.
Han: Hey, that wasn't my idea.
Chewbacca: He wanted to defend himself.
{beat}
Lando: Yeah. Good call letting Chewbacca handle your defence.