PVS-Studio warning V547 for Source SDK

unsigned  numbounce = 100;

int ParseCommandLine( int argc, char **argv, bool *onlydetail )
{
  ....
  numbounce = atoi (argv[i]);
  if ( numbounce < 0 )
  {
    Warning(
      "Error: expected non-negative value after '-bounce'\n");
    return 1;
  }
  ....
}

This suspicious code was found in Source SDK project by PVS-Studio static code analyzer.
Warning message is:
V547 Expression 'numbounce < 0' is always false. Unsigned type value is never < 0. Vrad_dll vrad.cpp 2412

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