[RobSis]

Unless you have a problem with running unknown compiled code, why not?

It's as easy as running '$ appletviewer URL'

[whamlastxmas]

Because having Java enabled for a browser is tremendously more risky than running a single application of unknown code.

[LukeShu]

As RobSis noted, you don't have to enable it in your browser, you can use appletviewer to run individual applets without the browser:

    $ appletviewer http://tropic.org.uk/~crispin/quantum/

And also, moderns browsers allow you to have the plugin installed, but disabled unless you activate it on a specific page.

[kecks]

Modern browsers... except Google Chrome, which has at least 40% market share.

Google Chrome does not support applets in any way since the deprecation of NPAPI.

[kecks]

I accidentally had appletviewer.exe it from the JDK, however the applet is served over http. I do appreciate this because I'd accidentally turned off HTTPS Everywhere and hadn't noticed (in weeks I suppose).

I think I'm not the target audience, I hope OP finds some good physicists to show this to :)