mount -u effects

[takCoder]

hi all,

i'm trying to move from freebsd to nanobsd on my server.. so i have a ro
partition.. but there are few times i have to upgrade my binary files on
this bsd server, so i need to change my ro partition to a rw one during
upgrade phase..

via googling, i found out that i can use "mount -u" on the mentioned
device, and then after doing whatsoever needed, when i restart my server
the ro permission will be back via applying old fstab..

i tested this method and it was ok for my need :)

but i have no idea what kind of effects it may have on my server.. i
couldn't find anything but suggestions about not to use this so often.. and
i really need to know why?? cause my bsd server is not allowed to be missed
almost at all..

i think that because this -u option is just increasing my permissions in
this case, there won't be a danger for my server. is that true?!

really waiting for your points on this case.
special thanks in advance,
takCoder