While keying of both connectors should be checked (and possibly only keying 1 pink w/ 1 red, since they seem to separate easier), the following is a solution to think about for safety purposes at least if more than 15 lbs of force to separate is necessary. At $3.00 each they are not too far out of the ballpark as far as costs and if the end that goes to the breaker is attached to the battery box by bolt attachment (as we have been doing the last few years), only 1 handle per battery attached Anderson SB50 is necessary. A small price to pay to save those students hands I would think. Just a suggestion. As, If I had to use a vice to disconnect one, I don't think I'd be reusing the connector again that was squeezed in that vice.
http://www.powerwerx.com/powerpole-a...andle-kit.html
They actually make a kit (that makes it easy), to attach it easily to that alum. or sheet metal battery box too! (though we usually just use 2 through bolts/nuts w/ countersunk heads on the battery side).
http://www.ebay.com/itm/Anderson-SB5.../270413183290?