Calling Landlords in LA - Any restrictions to be aware of?

[Tony Jordan]

I'm currently reading the ABCs of Real Estate Investing by Ken Mcelroy and he presents the strategy of calling landlords about selling. Before I do that, I was wondering if anyone knew of any general laws or restrictions which prevent this? I am aware there is a do-not-call list, but I'm not sure if this would apply, or how to even check if a number is on this do-not-call list.

I am located in Los Angeles if that brings more clarity.

Thanks!