The concept of bi directional printing is used in other high profile sports as well.
There is no prohibition in Cycling, Canoe Slalom, Rowing, etc.
Many software companies in Europe use these features as well.
Apparently there is some suspicion on the part of some members of the FIS Timing Working group that software is being used to manipulate the results. Therefore the printer could be logging false data as part of the deception.
Having a printer solely dependent on the timer for logging data does provide a separate audit trail that can be compared to the timing log to determine if the software is calculating the times correctly.
Any Chief of T&C that is doing their job is supposed to be checking this anyway.
I would say that it would be extremely difficult to fake a time in results software and "hide" it on the logging tape of a bidirectionally printing TIMY for example. The tape examples that I have seen from timers such as TIMY, and Microgate REI2 have both the raw TOD splits and the calculated net times on the tape. A person bent on altering the results would need to be in league with the firmware designer at each company to really be effective.
Tempest in a teapot. It seems to be another instance of trying to make software providers run around in circles to comply with situations that have never been proven to exist.