This video shows the B****e Carve's
leaning lock and release lever mechanism being used at time mark 1 minute 08 seconds and this video also shows the
leaning lock mechanism being engaged and disengaged also at the 1 minute 08 seconds time mark.
I rode one at the ICBF in Groningen last month.
The locking mechanism is really for loading and unloading only to keep the body level while you are distributing the load evenly or strapping children in.
You can ride with the lean locked out but it feels weird because your body naturally wants to lean into the corners. This is because of the Ackerman steering set up, which is far superior to the parallel wheel set up found on mule/donkey trikes which does nothing but scrub out tyres and waste energy.
It is not recommended that you switch between the two when riding as it is a cable operated spring loaded pin and locating hole set up that requires no more effort than pulling on a bicycle brake lever.