Walchschofer, from Germany, attended Challenge Wanaka at the weekend and said if Armstrong's admissions of doping led to sanctions being reduced or lifted, the law was likely to be on Armstrong's side if he wanted to compete in a Challenge event.
''If he was to go against us [in] court, I think he might win.''
That was despite Challenge being a private organisation and Walchschofer's view that ''we would not want to have him at any of our start lines''.
Walchschofer said many other athletes banned for doping had been persuaded not to compete in Challenge events when their bans ended.
''We have just talked to them and said, `We do not want to have you', and they did not come to race with us.''
He believed public opinion could strongly influence athletes' decisions and cited the case of German triathlete Nina Kraft, who was banned for one year after testing positive for performance-enhancing drug Epoetin.
Although she competed in ironman events after the ban ended, Walchschofer persuaded her not to compete in a Challenge event.
''She wanted to race with Challenge Roth [in Germany] but I contacted her and said, `Nina, we don't want to have you racing, and if you decide to push it our lawyers and everything will go public'.
''And she decided not to race.''
Both Walchschofer and Australian triathlete great Chris McCormack have told the Otago Daily Times they did not consider Armstrong to be a strong triathlete because he was not a good runner.
Walchschofer said he would not have made the top three in Wanaka.
''The field was much too strong.''
Walchschofer said Challenge was investing a lot of money in the fight against doping, testing athletes at every event and now taking ''blood controls'' before events in Europe as well as after.
''We want to have a clean and fair sport. It would be against our belief to have someone like Lance Armstrong even if the ban was lifted.''
Walchschofer said Armstrong had never raced in a Challenge event.
''We never approached him because ... for us it was obvious something was very, very wrong there.''
Walchschofer runs the Challenge triathlon series started by his late father, Herbert. It is the main rival to the Ironman triathlon series.
