I copied the following directly from the BAL FAQ section. Please note the last line.
"NOTE: BAL's chocks are designed for locking trailer tires when camping. They should be put in place after disconnecting from your tow vehicle and after putting down your stabilizing jacks. They should be removed prior to hooking up to your tow vehicle. Failure to do so may damage your chocks. To avoid undesired trailer movement when disconnecting or hooking up to your tow vehicle, a tire "wedge" should be firmly placed behind one, or preferably both rear trailer tires."
I know BAL products have a great reputation for adding stability, but there is no way I will unhitch my fiver without REAL wheel chocks in place (BAL calls them "wedges"). Semantics.