*public would affect other environments if no user assigned with role security or specific user secu

hi, as i know the security workbench priority will go 1st with user, then followed by role and *public..

can clarify if i applied below row security, would it affect all environment whereby those user w/o user or role security can not view company constant in P0000\AR

*Public CO F0010 00000 00000 NNN Y  ;  

some user failed to view company constant after above row security is applied...is that true ?

What if 

*Public CO F0010 00000 00000 YYYY  ;  

can users able to view all company constant...

would this *public take place all across all environment ?

pls enlighten...