ERISA requires disclosure of certain plan documents to participants including a summary plan description, statements, and notices. The problem is what do you do with people who aren’t participants such as potential employees?
If you’re scared about providing an SPD to a potential employee, maybe you should worry about what’s in your SPD. As for other information, you have to measure risk vs. offending the person requesting the information. You just don’t want to land in trouble by disclosing too much information and you also don’t want to offend those asking for information by just saying no especially if the goal is to hire them. There are certain things I wouldn’t disclose such as plan provider contracts and anything about plan governance.