John....
Usualy the knife is put on the high side of the Guard....
So when ya put it on the left side the knife will be on the lower side and have a better chance of catching the string, unless you position the guard correctly like it supposed to be worn...And you hold your bow right....
From my observation at countless shoots and pictures shown on this site, I have noticed a lot of people who dont position there Armguards correctly...
So the answer is yes and no, depends on you and how you wear your guard....
And of course this just my own opinon, from my limited experience....