Rant over a sloppy scammer

Occasionally I come across some really good scam attempts. But most of the time I'm surprised at how bad scams are presented. Let's look at a recent scam I received.

Using soft limits to prevent abuse with good user experience

When you develop a service you will probably run into a situation where you want to put in some arbitrary large limit on something to prevent bad behaving clients from using too much of your resources. This can be a max length of the URI, max length of each request header, max size of a request and so on. What we tend to do is often to return some kind of error when this happens and expect the client to fix their request if it is legitimate. But what if it is a legitimate request - just something you didn't expect to be valid? Or what if there is a bug in the client, but the user have no way of fixing the client but rely heavily on your service? Do you really want to completely break your users in these cases?