BUG: tail 5.93 -c argument is optional?

[sqweek]

 Hi, just noticed this odd behaviour from tail:

$ echo foo >bar
$ tail -c3 bar
oo
$ cat bar |tail -c3
oo
    # Working fine so far...
$ cat bar |tail -c 3
tail: cannot open `3' for reading: No such file or directory
    # What's that?? 3 is clearly the argument I intend for -c, not a filename!

 Interestingly, this works fine:
$ tail -c 3 bar
oo

 But this is somewhat questionable:
$ tail -c 3
tail: cannot open `3' for reading: No such file or directory