I have just been reading the ATTiny10 datasheet.
In the errata it states:
1. Programming Lock Bits
Programming Lock Bits to a lock mode equal or lower than the current causes one word of Flash to be cor-rupted. The location of the corruption is random.
Problem Fix / Workaround
When programming Lock Bits, make sure lock modeis not set to present, or lower levels.
Just so that I totally understand this, if I take the scenario of a virgin chip, and I have a batch file that programs my code, fuses and lock bits, then I'll be OK if I'm setting the lock bits to anything other than Lock Mode 1(which I assume is the unprogrammed, virgin state).
If, however, I need to re-program a chip, because I'm developing or updating firmware, I will be OK as long as I perform an erase cycle first.
Actually, I tend to use the STK500.exe for batch programming, so I will probably need to "learn" to use AVRDude or similar(provided that works for TPI mode).