This change from UUCP style lockfiles to flock() is still lacking follow-through of communication with the broader Linux community. Many Linux programs would still be using the older UUCP style locking of serial ports I think.
I've sent a message to the Serial HOWTO author David Lawyer regarding this issue. Note that this change seems to have been pioneered by Roger Leigh, who according to my searching on the Internet, seems to have left Debian Linux for FreeBSD in the last year or so. See his comments on the following article: http://changelog.complete.org/archives/9299-has-modern-linux-lost-its-way-some-thoughts-on-jessie So now this change is lacking its original pioneer and advocate.
