Er, no. Flying IFR does not relieve the crew of the responsibility to maintain a lookout. IFR and IMC are two different things. The vast majority of IFR is done in VMC. When flying IFR it is required to maintain a lookout anytime you are VMC, which is most of the time in the cruise. It is common to make a visual approach under IFR, maybe you wouldn't lookout but professionals know they are required to.