Not idealy mate no,imagine you hit into a small skimmer,and it snags the feeder,you snap off at the feeder rather than the hooklength leaving the small skimmer either attatched to the snag and the feeder or leaving it trailing a feeder behind it.Either way its pike fodder.
Slip a tiny ring or split ring to the end of your main line
Then slip your feeder on to the main line so effectively you've got the ring sliding up your line first, followed by your feeder
Then tie the end of your main line to the ring using a half blood knot (or similar)
You should now have your feeder sliding in a loop
Then decide how much free movement you want from your feeder and pull the ring up the main line to suit
Pinch the end of the resulting loop and tie a double overhand loop knot into this
Then attach your hooklength to this second loop
What you have is a feeder that is contained within a loop of line but if your mainline snaps the feeder will pull free from it as the line slips through the ring
... have I explained it enough or confused everyone lol?
I use the type of rig you mention, but put the feeder on the line first so it is free-running. Then when tying your loops, put a rubber bead inside the big loop. This then acts as a buffer on the knot and when you get a bite, the feeder will hit the knot at the line end of the loop, acting like a bolt rig. Should the need arise, the feeder can slide over the knot and up the line, therefore being free-running and safe.