Hmmm, well something terrible has gone wrong for me - I've tried to compile head and it failed for some reason. Git bisect told me:
$ git bisect visualize
commit 5ef60412db146a7bdb47e0fb8b9f69bd9652b7ff
Author: Timothy Stack <redacted>
Date: Sun Jul 12 09:57:02 2015 -0700
[pt] pass search query to papertrail
commit 7ef92dab79877f184622f9d33b9dc8b41248b303
Author: Timothy Stack <redacted>
Date: Sat Jul 11 16:32:48 2015 -0700
[format] try to validate formats against a given file
$ git bisect log
git bisect start
# bad: [d4e7f83a77e95d230f4748540b37a6454b6b50b5] try to use travis containers
git bisect bad d4e7f83a77e95d230f4748540b37a6454b6b50b5
# good: [87ec101f9c379ecd76dfa19e20a44c64d5ba6fb7] [fmts] log format contributions
git bisect good 87ec101f9c379ecd76dfa19e20a44c64d5ba6fb7
# good: [7679599afc1d3e71abac950098b8d185208941b0] fix a refactor error
git bisect good 7679599afc1d3e71abac950098b8d185208941b0
# good: [f392822aa8f7b4b5b4810211ba190c87f99f9e9e] [parse] show the path of the pattern used to parse the top line
git bisect good f392822aa8f7b4b5b4810211ba190c87f99f9e9e
# bad: [5ef60412db146a7bdb47e0fb8b9f69bd9652b7ff] [pt] pass search query to papertrail
git bisect bad 5ef60412db146a7bdb47e0fb8b9f69bd9652b7ff
I'm running Red Hat Enterprise Linux 7 Workstation, so I know that it's not exactly cutting edge :-)
However, the good news is that the latest version I can get to compile does do as you say - :pipe-to works. Dunno what was going on there.