Can members see who else received the email?

No.  Each email is sent individually.  Members can't see who the other recipients of the email are. So sending "BCC" or "blind carbon copy" is not required.

This is all done by default and cannot be changed, for privacy and data protection reasons.

Another benefit of WebCollect sending a separate individual email to each recipient, is that the content of the email can also be customised "per recipient" using "tags".