Take a look at this from the Scratch Wiki:

Scratch Wiki’s page on spam wrote:

A spam project is easy to spot. They are projects with no exact purpose, containing either gibberish or nothing at all. Inappropriate projects are also counted as spam. A large proportion of project spam comes from attempts to get rare project IDs.

When someone attempt a milestone, what usually happens is that they copy a project as fast as possible when the project ID is close enough to the milestone, check the projects for the milestone, and then delete the excess projects created from this. Does this make attempting milestones discouraged or not allowed?

Attempting URL milestones is allowed, but project spam is not.

You can go for a URL milestone by creating a project at the right time, but using the brute-force method of rapidly clicking Create is spam and therefore not allowed.

Voxalice wrote:

You can go for a URL milestone by creating a project at the right time, but using the brute-force method of rapidly clicking Create is spam and therefore not allowed.

I think manually copying it isn’t exactly spam, but I heard (removed by moderator - please don't name names) used a SCRIPT to spam projects to get 1000000000 and the projects directly before and after it.

No, not if it results in a whole bunch of empty projects. It's not a creative activity and it is wasting site resources.

My judgement is that the less excess projects with no content are created, the better.

Even though I have some “nice” URLS, No.