Sabino's don't HAVE to be roaned. For example. Red Man is a minimal Sabino (defined by his lip spot and pointed leg markings) but is not roaned at all.
From the registry;
"...Basically all white markings are acceptable with the exception of ANY spots or markings which can be directly associated with another spotting gene such as Tobiano or Frame."
"White roaning, ticking, graying are accepted with the same constraints. If a horse is gray or roan the base color for that horse should be identified on the application if known and the appropriate box to indicate roan or gray checked if applicable. True roan should not be confused with Sabino roaning. To be a true roan one parent must be a true roan. To distinguish by appearance, True Roans have dark faces and legs and manes and tails unless the Sabino roaning influence has covered that."
Prissy would be defined as a Sabino because of:
Unusual bald face markings
Unusual leg markings
'Lacy' type markings on the rump
Jet could or could not be defined as a Sabino because of his lip spot and pointed leg markings. But he could also not be accepted because his markings could also be defined as a Tobiano.
Wait! I'll fix it....