Funny - maybe it was just a temporary glitch. The following code works nicely for me (as a proof of concept).

use YAML;
use XML::Simple;
use LWP::UserAgent;

print Dump(
  XMLin(
    LWP::UserAgent->new->get(
      "http://jobs.perl.org/rss/standard.rss"
    )->content()
  )
);
[download]

Maybe you just bumped into an update glitch or something similar. Still you're right - there will no doubt be some unexpected things that need to be taken into account.