how safe is kern.geom.part.check_integrity=0 ?

[Julien Cigar]

Hello,

I upgraded today a gmirror'ed machine from 8.2-RELEASE to 9.0-RELEASE, 
but the system fails to mount my root mirror with an error 19 when I try 
to boot with the 9.0 kernel.
I read that adding kern.geom.part.check_integrity=0 could solve the 
problem, but I haven't found any statement on the safety of setting 
this.. Any idea if it's "safe" ?
Also I'm a bit disappointed that there is no entry in /usr/src/UPDATING 
about this issue ...

Thanks,
Julien