EMC stability

Many thanks to the folks who have answered my questions so far on EMC
and to Ray Henry and Paul Corner who are looking into the previous
G44 question I asked.
Contary to popular myth I read the FAQ and also a lot of what is in
the Linux/emc files.
I came across one referance to one of Matt Shavers customers who
noted that "We are still having run aways"
Can anyone shed light on this, Matt? It seems a little worrying if
this can happen. I often set my machine running and walk away into
the other shop to carry on bench work.
Second thing I picked up was a recent post about the BDI install
resetting the referance points after a G30, end of program move. Has
this been dealt with yet?

John Stevenson