The element children of details that are not recognized get added as wildcards, and can be accessed this way:
detail = event.detail
for elt in detail.wildcardElements():
print elt
However, those elements are both DOM instances (one for _flow-tags_, one for shape). Normally PyXB will convert elements for any bindings that have been loaded into the application, though they'll still be stored in the wildcardElements() array. That's not happening here because the two schemas you're using both have absent namespaces, but are being translated as independent schema. There is no element _flow-tags_ in either schema, but the shape is not being converted to a binding because the elements from the Shape schema cannot be recognized within the absent namespace used for Event.
Not knowing where those schema came from I can't tell how they're supposed to be used, but one approach would be to combine them into a parent schema as in:
<xs:schema xmlns:xs="http://www.w3.org/2001/XMLSchema"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
elementFormDefault="qualified" attributeFormDefault="unqualified">
<xs:include schemaLocation="Shape.xsd"/>
<xs:include schemaLocation="Event.xsd"/>
</xs:schema>
Then build bindings from this:
pyxbgen -u combine.xsd -m combine
Then you can import those bindings, which have both Event and Shape components, thusly:
import pyxb
import combine
xml = '''
<event how="h-p" opex="e-TEST" qos="7-r-g" stale="2014-04-21T20:50:01.85Z" start="2014-04-21T20:48:01.85Z" time="2014-04-21T20:48:01.85Z" type="a-n-A-M-F-R-Z" uid="6716" version="2.0"><detail><_flow-tags_ debug="2014-04-21T20:48:01.00Z" /><shape><ellipse angle="33" major="44" minor="22" /><polyline closed="1"><vertex hae="1" lat="44" lon="-77" /></polyline></shape></detail><point ce="122.8" hae="817.2" lat="42.5612194" le="431.3" lon="-71.302077" /></event>
'''
try:
event = combine.CreateFromDocument(xml)
except pyxb.IncompleteElementContentError as ex:
print ex.details()
You'll see that the example document is not valid because of the following error:
The containing element polyline is defined at Shape.xsd[65:12].
The containing element type <class 'combine.CTD_ANON_2'> is defined at Shape.xsd[71:16]
The <class 'combine.CTD_ANON_2'> automaton is not in an accepting state.
Any accepted content has been stored in instance
The following element and wildcard content would be accepted:
An element vertex per Shape.xsd[73:24]
No content remains unconsumed
If you look at Shape.xsd line 73 you'll see that a polyline requires at least two vertex elements. If you then correct the document to have a second vertex, then the first member of details.wildcardElements() will still be a DOM Element instance, but the second will be a shape binding.