Unconfined processes tend to stay unconfined. That is what uses expect,
telling them that they are executing an uconfined process that suddenly
becomes confined, seems wrong to them. That being said, you can end up
with mislabeled files because of this.
So
unconfined_t -> squid_exec_t -> unconfined_t
But unconfined processes starting init scripts have a transition
unconfined_t -> initrc_exec_t -> initrc_t -> squid_exec_t -> squid_t
So any time you are using a confined process you should use the init
script to start them, otherwise you could get mislabeled files.