From PsychoWiki

Checking log file consistency could be useful.

Here's my tutorial for doing that: http://www.psychostats.com/forums/index.php?showtopic=16822&st=0&p=91273&#entry91273

I have no idea how often that happens or why actually, but it seems to happen occasionally atleast.

http://www.psychostats.com/forums/index.php?showtopic=17023 - There's the other guy who has broken log file. He would have found it this way too.

Broken log files seem to cause weirdness in hitbox percentages and such.

Difficulty level for this is above average because external programs are required and command line usage. Still, it's good to know information. Even pro users sometiems lack this basic knowledge.

Probability level for someone actually using these: very low ;-)

Probability for someone reading this: extremely low, if you read this please contact me :-)