U-joint?

Had a front U-joint come loose on me the other day. Fortunately it didn't come of completely before I was able to pull off the road:steering:

I went ahead and had it towed to a shop and they were able fix it by just replacing the joint. One thing concerns me however, they told me that they didn't have press the bearing caps in the slip yoke end? The mechanic told me that the c-clip should be enough to keep it from coming out. What do you all think?
Are you saying that they just slid in? They should be a press fit. Is it possible they got the wrong u joints, or had the yolk egg out? I would never trust just the c clip to handle the torque