That awful Plus sign has lost me at least one prime gift-certificate becuase the huge button below the entry box can't be "unclicked" and is the natural thing to click if you aren't being super observant. To make matters worse, as far as I can tell there is no way to recover the code. This happened to me some time ago and almost happened to me today except I went ahead and bought something that I hadn't really intended to purchase just to be sure not to lose it. This really should be fixed. At the very least, a quick javascript check to alert the careless user that they entered a GC but didn't "Plus" it when hitting that purchase button. 

I will be sure our team sees this comment so that we can address it. Thank you for your report and suggestion.