Several reports in forums that the trackpad in Thinkpad's "disable tapping" would not stick, it reset to enable after reboot.
<http://forums.lenovo.com/lnv/board/message?board.id=T_Series_Thinkpads&thread.id=1945>
<http://forum.thinkpads.com/viewtopic.php?p=426489&sid=4f47d55d8490d86e5e214cb8bfe0a8b2>
If you do a process monitor or SynTPEnh.exe, it looks like that the program fails to save any change to the registry.
The value of DWORD
HKEY_CURRENT_USER\Software\Synaptics\SynTPEnh\UltraNavPS2\TrackPointModeFunction
changes to if you make these changes
0x11 - default
0x21 - enable slow motion pointer
0x41 - scrolling and tap zones only
but not on enable/disable tapping.
Definitely looks like something Lenovo and/or Synaptics has to modify in the driver to fix, no much can be done on the user end to change that.