Wouldn't your flash just slide out of this PC Adapter?

[gl600]

[ame=http://www.amazon.com/Adorama-Hot-Shoe-PC-Adapter/dp/B00009R8G3/ref=sr_1_2?ie=UTF8&s=electronics&qid=1265664499&sr=8-2]Amazon.com: Adorama Hot Shoe to PC Adapter, Single Outlet without Connecting Cord.: Electronics[/ame]

Maybe I am missing something, it looks like there is nothing from stopping a flash from slipping out.

This one looks better:
[ame=http://www.amazon.com/Seagull-SC-2-Flash-Adapter-Socket/dp/B00281Y6FO/ref=sr_1_8?ie=UTF8&s=electronics&qid=1265664499&sr=8-8]Amazon.com: Seagull SC-2 Flash Hot Shoe Adapter with PC Sync Socket: Electronics[/ame]

Am I missing something?

 

[IgsEMT]

when you mount a flash onto the camera, there's a lock that you have to activate to prevent the unit from falling out. same idea is here

 

[Big Mike]

It depends on the flash.
Many hot shoe flashes will have a locking/tightening device that helps to snug up the connection...but it's not a guarantee that your flash won't fall out.

 

[gl600]

As an example the SB-600 and Sb-800 don't have a clamp or tightening mechanism, they have a tiny bolt that locks it in place... that would be useless for the pc adapter.

 

[KmH]

The first one you linked to has a spring steel bottom that puts upward tension on the speedlight foot.

The second will let the speedlight fall out in one direction only.

I use cold shoes that have a screw that is tightened from the side to hold the speedlight in place. I also use some gaffers tape as added insurance.