This one shows no newline before the music starts: 
X:0
T: No Score
C: The Traditional Tune Archive
M:
K:
x


X:1
T: 1 Speed the Plough
M:4/4
L:1/8
C:Trad
K:G
|:GABc dedB|dedB dedB|c2ec B2dB|c2A2A2BA|
|GABc dedB|dedB dedB|c2ec B2dB|A2F2G4:|
|:g2gf g2Bd|g2fe dBGB|c2ec B2dB|c2A2A2df|
|g2gfg2Bd|g2fe dBGB|c2ec B2dB|A2F2G4:|

Chris
from thesession:

X: 1
T: Me Mother Won't Let Me Marry
M: 6/8
L: 1/8
R: jig
K: Dmaj
DFA B2A|FGF F2E|DFA B2A|G3-G2 F|
EGE EFG|c2c c2B|A^GA B2A|F3-F2 E|
DFA B2A|F=GF F2E|DFA B2A|G3-G2 F|
E2E EFG|c2c c2B|A^GA ABc|d3 e2 z|]
f2f f2e|d2d d2e|ded c2d|e3-e2 f|
g2g g2e|c2c c2B|A^GA B2A|F3-F2 d|
f2f f2e|d2d d2e|ded c2d|e3-e2 f|
g2g g2e|c2c c2B|A^GA ABc|d3-d2 z|]

In this document, small bits of abc are interpreted
X: 1
T: 2 body child
A

X: 1
T: 3 div child
A

X: 1
T: 4 div div child
A

This also works when in a paragraph
X: 1
T: 5 Here is a title
K: Emin
CDEFGABcdefgab

On a new line inside a pre 

X: 1
T: 6 Cooley's
M: 4/4
L: 1/8
K: Emin
|:D2|EB
X:1
T: 7 begin
G

This is mid-line.
X:1
T:8 middle
G

X:1
T:9 blank lines on either side
G

in the middle it should work
X:1
T:10 end
G
X:1
T:11 begin
K:G
G

Here is some text between tunes.
X:1
T:12 middle
G

X:1
T:13 blank lines on either side
G

in the middle it should work
X:1
T:14 end
G