For what I am used, when a secret key is exported, the key password should be
asked. 
The same applies for when a revoke key is exported. 
On this new install of 42.2 I experience the same problems as I have in the
past. When they happen the system gets nearly unusable. They always come
together, so I report them here. 
a) first problem you encounter is that the password insertion field does not
react any more. After resetting the PC you find:
1) this is a luks encrypted system with password protected grub, a notebook. 
Before this event no problem. After(!) this event you have that external
usb-keyboards works, until you reach LUKS. Then you are forced to enter the
password over the notebook keyboard because the system does not recognize any
USB any more (no mouse no keyboard). So now you enter the password via the
notebook keyboard, the system starts and all seems normal again (note that this
is not normal because a fresh install never has this problem).
b) you reach the desktop, start kontact/kmail and since you protected the
password with kgpg you find that the password does not react. Before I did not
have any problem. Then, I installed kwalletmanager. After the install the
password input worked again until the next reboot. This time I had to type the
password 8 times to get the wallet to open. 
Now I wanted to see whether something was wrong and opened kgpg. So now I can
export a public key, a secret key and a revoke without password? So that would
mean if you use gpg-keys to protect you wallet, no problem to get hold on you
secret key? 
I am used that you have to type in the password to export you secret key. 
And also issuing a revoke key should IMO always(!) require a password.
Otherwise maybe I did misunderstand the principle of the need of a password in
kgpg. 
Please let me know if this is a new feature.