An exception exists for TLEs redistributed by CelesTrak.com. Sources: http://celestrak.com/NORAD/elements/notice.asp#Update16 and personal correspondence with the operator.
(Note also that the Space Track terms do not prohibit individuals from requesting accounts for personal use.)
Re:SpaceX Falcon 9 – Possible Explosion
by toomuchtodo on Tuesday October 01, 2013 @02:36PM
(#6478158)
Aren't the works of the federal government, by letter of the law, public domain? Wouldn't this negate their terms of service?
NORAD's Space Track service makes the raw two-line elements available, but over the recent decade they have tightened usage and distribution restrictions. By the letter of the terms of service, one who downloads the data may not disclose the raw data or anything derived from it.
https://www.space-track.org/documentation#/user_agree
As a result, amateur satellite tracking groups have to 'disregard' Space Track data and determine orbital elements through their own observations.