Update:
Following Rockstar’s massive update to Red Dead Online last week, the glitch discussed in this article has since been patched.
Marigold (Goldie) Bartlett and the crew of players who were pushing through the boundary map of Red Dead Online – The Grannies – contacted IGN with their own update after the patch, confirming they no longer could push through the map like they had for months previously.
“It immediately became clear that it wasn’t going to work, but we kept trying,” Bartlett said. “Quietly, we gave up after about 10 minutes. The mood was low.”
Source: IGN.com Red Dead Online Players Can No Longer Break Out of the Map