[PEN-TEST] advertising private IP numbers?

[securitygeek () HUSHMAIL COM]

Below is part of traceroute that I grabbed... Is it normal to advertise
non-routable/interal IP's like this? If it isn't, what mischief can be made
easier to accomplish when this is done?

 18    80 ms   100 ms    80 ms  bb1-pos3-0-0.rdc1.va.home.net [24.7.73.110]
 19   100 ms   140 ms   110 ms x.x.x.home.net [24.x.x.x]
 20    81 ms    90 ms   150 ms  10.252.60.6
 21   331 ms   320 ms   411 ms  192.168.0.98
 22   190 ms   160 ms    90 ms  x.x.x.253
 23   150 ms   191 ms   140 ms  x.x.x.10