Does Drawing on Experience Infringe on Other's IP?

Daniel Paull asks: "I recently asked one of our developers to draw up a design for a specific component. After a few hours he returns telling me that he'd solved a very similar problem a previous place of employment and that they had developed a "neat" solution. The developer then became concerned that a ground-up re-implementation of these design patterns and principals may infringe on the other companies intellectual property or breach some copyright laws. This developer is talented and experienced - that's why we hired him. The question is, at what point does 'drawing on experience' cross the line and invade others IP?"

Comments

Translation:

[Bonker]

Translate: "I'm afraid that if I help you with this solution, I'll be violating my previous employer's intellectual property rights."

as:

"I know you hired me because of my work in your field, but frankly, I'm lazy. I can't surf porn and read messageboards all day if I'm working on this solution for you. Here's a tidy excuse so you can feel better about the money you're wasting on me and my blatant goofing-off habit."