I'm late to this party, but here's how I deal with this: let the character escape. And now he's guilty of something far worse than whatever minor crime got him locked up originally. Jailbreak is a felony, maybe even a capital offense. He's suddenly notorious; his name is known to every guard, he's that Scofflaw, that That Jailbreak Guy, and no mere petty criminal. Word spreads and the population fears him because he's a Threat To Society, Unmutual, whatever label you like. Wanted posters go up everywhere. Only other criminals will deal with him. And if a few guards run across him and he happens to oops, die in the intervening attempt at arrest... the legal system will turn a blind eye to it because you just can't have people escaping jails all the time, so we'll just use death as a prison. Knock those chains, buddy.

If this is likely to be a thing the players run into, I'd let them hear some legends of this happening, early on. A "Wanted dead or alive" poster in an Inn and a Innkeeper who knows the story of Blake the Infamous... if the players don't take the hint, one of the characters will eventually serve as an object lesson to the rest.

It's just sense. Prisons, especially in small towns, simply don't have the economic resources to handle unusual cases like mages. They might take a few simple precautions, but even the previously stated idea of putting someone in armor all the time, while brilliant, is expensive (and they have to be let out of the armor eventually.) Societal pressure is cheaper and very effective.

Here's how I deal with this: let the character escape. And now he's guilty of something far worse than whatever minor crime got him locked up originally. Jailbreak is a felony, maybe even a capital offense. He's suddenly notorious; his name is known to every guard, he's that Scofflaw, that That Jailbreak Guy, and no mere petty criminal. Word spreads and the population fears him because he's a Threat To Society, Unmutual, whatever label you like. Wanted posters go up everywhere. Only other criminals will deal with him. And if a few guards run across him and he happens to oops, die in the intervening attempt at arrest... the legal system will turn a blind eye to it because you just can't have people escaping jails all the time, so we'll just use death as a prison. Knock those chains, buddy.

If this is likely to be a thing the players run into, I'd let them hear some legends of this happening, early on. A "Wanted dead or alive" poster in an Inn and a Innkeeper who knows the story of Blake the Infamous... if the players don't take the hint, one of the characters will eventually serve as an object lesson to the rest.

It's just sense. Prisons, especially in small towns, simply don't have the economic resources to handle unusual cases like mages. They might take a few simple precautions, but even the previously stated idea of putting someone in armor all the time, while brilliant, is expensive (and they have to be let out of the armor eventually.) Societal pressure is cheaper and very effective.