Hi David,
Yes, you can do this with the following:
from arcgis.gis import GIS
from arcgis.features import FeatureLayerCollection
gis = GIS("https://www.arcgis.com","jskinner_CountySandbox", "*******")
search_results = gis.content.search('title: MD_Traffic_Cameras', 'Feature Layer')
traffic_cameras_item = search_results[0]
trafficCameras_flc = FeatureLayerCollection.fromitem(traffic_cameras_item)
print(trafficCameras_flc.properties)
update_dict = {'capabilities':'Query,Extract'}
trafficCameras_flc.manager.update_definition(update_dict)
print(trafficCameras_flc.properties)
The service previously only had 'Query' capabilities. The above code will now enable 'Extract' which will allow others to export the data.