You seem to have underestimated the seriousness of what I'm raising.

Most shopping cart implementations out there, in Perl or otherwise, tend to be crap. It is very common for them suffer from one or more of the problems that I listed. In order those problems allow people to steal products from you, steal your database from you (mmm...credit cards!), creates a significant usability problem, and allows your site to be defaced. Each afflicts a large fraction of shopping cart implementations. And yes, there is nothing Perl-specific about any of them.

In short the problems that I've listed are not just theoretically possible, they are widespread. And they are not just "the odd thing" to miss, they are serious issues that you really don't want to miss.

If you've looked at "a fair number of shopping carts" and have never seen these problems, then I must conclude that you've either been unbelievably lucky or else you do not know to look for them. I choose not to believe in luck, you have seen bad shopping cart applications. In which case your opinions on quality must be wrong. Dangerously so.

Now I could make this point in a gentle way. And run the risk that you would be left thinking that I'm just presenting a minor consideration and your advice was mostly fine. Or I could, as I have done, make the point bluntly enough that there is no possibility of your missing the fact that I think your judgement was wrong. At the cost of likely offence.

I try not to offend lightly. And I did not lightly choose to do so this time.