Yes. You are accessing paid content without a license. Under the DMCA, circumventing a digital lock (Steam Stub DRM) is a violation.
Furthermore, the modding community is rallying. New mods like "Fallout: London" require the GOTY edition patched to a specific version. Using an unlocker often breaks compatibility with total conversion mods because they look for the official .esm file signatures. The Fallout 4 DLC Unlocker is a double-edged plasma rifle. On one hand, it offers freedom from Bethesda’s often-overpriced DLC model and allows modders to access assets they can’t afford. On the other hand, it is a minefield of malware, legal risk, and save-game corruption. fallout 4 dlc unlocker
If you value your Steam account and your PC’s health, you should wait for a sale. The Fallout 4: GOTY Edition is frequently cheaper than a cup of coffee. However, if you are a veteran modder who owns the DLC physically but Steam refuses to recognize it, the unlocker (specifically CreamAPI) is a legitimate tool for digital preservation. Furthermore, the modding community is rallying
Bethesda (now owned by Microsoft) has a curious history. They have never sued an individual for using a DLC unlocker; they simply patch the loopholes in updates. While community managers have called it "unfair to developers," no major legal action has occurred against end-users. The Fallout 4 DLC Unlocker is a double-edged plasma rifle