JRT, when we got our C310 the previous owner told us that we needed to keep our foot near the end of the leg (at the floor) because if someone hit the leg the table would crash down. Also, the table was not flat, it was higher at the leg end. We did this for most of the summer until one day it all didn't make sense. I looked under the table and noticed that the hinged part of the leg had a circular piece of metal that looked crushed. The leg is supposed to slide up into this piece, but couldn't. I took it apart, re-formed it to original, and the leg slides up into a locking position. When you want to fold the table, raise the end of the table, the leg slides out of the mystery piece, then you tuck the leg up and lower the table, then use the 'special' bungee cord to secure it.
When you look at it, this should make sense.
Cheers
dj