While I completely agree (and my company requires) that strobes must be turned on when on any runway, whether crossing, TIPH, etc..., you guys are quoting the reg wrong.

91.209 (b): No person may operate an aircraft that is equipped with an anticollision light system, unless it has lighted anticollision lights. However, the anticollision lights need not be lighted when the pilot-in-command dtermines that, because of operating conditions, it would be in the interest of safety to turn the lights off.

The reg states that you cannot operate an aircraft with the anticollision (strobe) lights off. That would include taxiing, takeoff, cruise, landing, etc... The loophole is the second sentenance that addresses if its a matter of safety, then don't use them. That's why we usually turn them off, to not blind other pilots. But that level safety (not blinding someone else) gets trumped by the safety of operating an aircraft on a runway (turn them on when on a runway). A bit off subject, but that's why it is legal to turn strobes off at night in IMC...so you don't blind yourself and not see the screens/guages.