Build 1546 changes the "allow untrusted URLs" setting to no longer allow all URLs on public and group public instances, and instead offers world creators the option to whitelist domains for those instance types.
A preferred alternate solution would be to instead prompt users with a notification when an untrusted URL is being used, with the options to:
  1. Allow this time/this instance
  2. Whitelist URL (allow permanently until revoked)
  3. Blacklist URL
This would provide users with the granularity to avoid malicious URLs without explicitly limiting the content that may be played in public/group public instances.