On Sat, 7 Aug 2004, Eric Johnson wrote:

>   Why would one or two members receive probes on a daily basis
>whereas the rest of the members receive the probe on a quarterly basis as
>specified?

Are the probes being rejected? If so, that would explain why.
Send email to the addresses in question to see if those addresses
are actually valid. I suspect the probes are being forwarded to
non-functioning email addresses.