I have to admit, mine have been stored in locked gun cases for transport and storage, but not trigger locked.
They are still tranported the same way, but they now go into my gunsafe when they are not being used.
I already can see the argument that trigger locks are an added expense when getting into the sport, but I can't support that. Trigger locks are $15 a piece and an EL-CHEAPO lock for your transport cae can be had at the local corner store for under $3.
There is just no excuse.