I have a few Emersons that are like that. For me, the locks function without fail even when I put extra stress on them to see if the locks would disengage. I wouldn't worry about it unless the knife has vertical (up/down) blade play or if the lock consistently touches the opposite liner through unwaved opening.
One thing you could try before sending it in, is to rotate the blade stop pin 180 degrees or to disassemble the knife and recenter the blade. Sometimes after use, the body screws get a little loose and cause the liners to very slightly shift in position. This will change the blade centering and therefore also the lockup of the knife. I'm sure others will have some advice for you as well, but if you do not feel the knife is safe, send it in. You don't want any doubt in your mind about the integrity of your knife when you are using it.