Happens to me all the time and there's nothing wrong with "lurkers". Often they think that by joining this site (or others like it) that they're risking exposure. I understand their point of view but they have to pass screening just like everyone else. I can't say if non-eccie members are better than eccie-members. I'm very fortunate to have wonderful clients who come from many sources.
If you're concerned about the quality of the potential client, limit the amount of contact info you publish. It'll add a couple more steps to your screening process but you have to screen in a way that makes you feel comfortable and safe. Ease fix
Good luck!