Seems PA is getting the correct active port:

$ pactl list sinks
Sink #0
	State: SUSPENDED
	Name: sink.primary
	Description: Droid sink primary
	Driver: module-droid-card.c
	Sample Specification: s16le 2ch 44100Hz
	Channel Map: front-left,front-right
	Owner Module: 4
	Mute: no
	Volume: front-left: 65536 / 100% / 0.00 dB,   front-right: 65536 / 100% / 0.00 dB
	        balance 0.00
	Base Volume: 65536 / 100% / 0.00 dB
	Monitor Source: sink.primary.monitor
	Latency: 0 usec, configured 0 usec
	Flags: HARDWARE DECIBEL_VOLUME LATENCY 
	Properties:
		device.description = "Droid sink primary"
		device.class = "sound"
		device.form_factor = "internal"
		droid.hw_module = "primary"
		device.icon_name = "audio-card"
	Ports:
		output-earpiece: Output to earpiece (priority: 200)
		output-speaker: Output to speaker (priority: 300)
		output-wired_headset: Output to wired headset (priority: 400, not available)
		output-wired_headphone: Output to wired headphone (priority: 400, not available)
		output-bluetooth_sco: Output to bluetooth sco (priority: 100)
		output-sco_headset: Output to sco headset (priority: 100)
		output-sco_carkit: Output to sco carkit (priority: 100)
		output-aux_digital: Output to aux digital (priority: 100)
		output-analog_dock_headset: Output to analog dock headset (priority: 100)
		output-digital_dock_headset: Output to digital dock headset (priority: 100)
		output-fm_tx: Output to fm tx (priority: 200)
		output-speaker+wired_headphone: Output to speaker+wired headphone (priority: 100)
		output-parking: Parking port (priority: 50)
	Active Port: output-speaker
	Formats:
		pcm

Sink #1
	State: SUSPENDED
	Name: sink.fake.sco
	Description: Null Output
	Driver: module-null-sink.c
	Sample Specification: s16le 1ch 8000Hz
	Channel Map: mono
	Owner Module: 5
	Mute: no
	Volume: mono: 65536 / 100% / 0.00 dB
	        balance 0.00
	Base Volume: 65536 / 100% / 0.00 dB
	Monitor Source: sink.fake.sco.monitor
	Latency: 0 usec, configured 0 usec
	Flags: DECIBEL_VOLUME LATENCY 
	Properties:
		device.description = "Null Output"
		device.class = "abstract"
		device.icon_name = "audio-card"
	Formats:
		pcm

Then plugging in a headphone goes to:

$ pactl list sinks
Sink #0
	State: SUSPENDED
	Name: sink.primary
	Description: Droid sink primary
	Driver: module-droid-card.c
	Sample Specification: s16le 2ch 44100Hz
	Channel Map: front-left,front-right
	Owner Module: 4
	Mute: no
	Volume: front-left: 65536 / 100% / 0.00 dB,   front-right: 65536 / 100% / 0.00 dB
	        balance 0.00
	Base Volume: 65536 / 100% / 0.00 dB
	Monitor Source: sink.primary.monitor
	Latency: 0 usec, configured 0 usec
	Flags: HARDWARE DECIBEL_VOLUME LATENCY 
	Properties:
		device.description = "Droid sink primary"
		device.class = "sound"
		device.form_factor = "internal"
		droid.hw_module = "primary"
		device.icon_name = "audio-card"
	Ports:
		output-earpiece: Output to earpiece (priority: 200)
		output-speaker: Output to speaker (priority: 300)
		output-wired_headset: Output to wired headset (priority: 400, not available)
		output-wired_headphone: Output to wired headphone (priority: 400, available)
		output-bluetooth_sco: Output to bluetooth sco (priority: 100)
		output-sco_headset: Output to sco headset (priority: 100)
		output-sco_carkit: Output to sco carkit (priority: 100)
		output-aux_digital: Output to aux digital (priority: 100)
		output-analog_dock_headset: Output to analog dock headset (priority: 100)
		output-digital_dock_headset: Output to digital dock headset (priority: 100)
		output-fm_tx: Output to fm tx (priority: 200)
		output-speaker+wired_headphone: Output to speaker+wired headphone (priority: 100)
		output-parking: Parking port (priority: 50)
	Active Port: output-wired_headphone
	Formats:
		pcm

Sink #1
	State: SUSPENDED
	Name: sink.fake.sco
	Description: Null Output
	Driver: module-null-sink.c
	Sample Specification: s16le 1ch 8000Hz
	Channel Map: mono
	Owner Module: 5
	Mute: no
	Volume: mono: 65536 / 100% / 0.00 dB
	        balance 0.00
	Base Volume: 65536 / 100% / 0.00 dB
	Monitor Source: sink.fake.sco.monitor
	Latency: 0 usec, configured 0 usec
	Flags: DECIBEL_VOLUME LATENCY 
	Properties:
		device.description = "Null Output"
		device.class = "abstract"
		device.icon_name = "audio-card"
	Formats:
		pcm