Example:

# This the default session launched by xfce4-session if the
# user hasn't saved any session yet or creates a new session.
[Failsafe Session]
Count=5
Client0_Command=xfwm4
Client0_PerScreen=False
Client1_Command=xfce4-panel
Client1_PerScreen=True
Client2_Command=xftaskbar4
Client2_PerScreen=True
Client3_Command=xfdesktop
Client3_PerScreen=False
Client4_Command="hotkeys -Z"
Client4_PerScreen=False

The hotkeys command won't run.