DarkRP is a very poorly coded gamemode
That's it in a nutshell.
Any decent gamemode author should write it's
own restrictions for <tools><weapons><sents> <whatever else shouldn't be used in the
gamemode.
URestrict was meant for Sandbox, because Sandbox in itself only allows little control of the weapons, tools and sents
Gamemodes have easy commands to control such behaviors. No version of DarkRP ever hacked, because the base was poor to begin with, ever included proper controls for Sandbox based items use.