Ask Can a client on a freelance platform ask a freelancer to sign a separate NDA outside the platform?

[Edward22]

It is common for clients to want to protect their ideas and business information when working with freelancers. Some clients feel the platform agreement is not enough, so they ask for a separate NDA to be signed outside the platform. I have seen this come up in discussions, and people seem to have different opinions on whether this is allowed or even safe. Does signing documents outside the platform put you in any kind of risk with the platform's rules?