@XX_Doggoa Assuming Roblox uses basic security (just checking that the player that they think fired the event's IP address and what IP address the player is using right now), that probably would not be possible. However, it might be possible to make Roblox think it came from another user like by using the same network (since most/all routers uses NAT making websites think everyone on their website are one person and might not work if they switch to an IPv6 only router/IPv6 only world since there's no reason to have NAT anymore.) and modifying the request internally. It might also be possible (not sure about this) to modify the network packets to make it seem like another IP (player) sent it and the request to make it appear like it came from them. However, the latter is not likely to happen since there's no way (with basic security) for one person to know other people's IP address in the game (unless you're on the same router). Even if they did, the ISP might detect that the IP was modified (not sure about this either but it might detect the IP address belongs to another ISP) and not send it.
TL;DR: It's should be unlikely unless the hacker is on the same router as the the other person they want to impersonate.