Because you are concerned about the potential for a bid protest, you must consult immediately with your activity's legal counsel. That being said, you may be able to leverage the GAO decisions if you decide to award to the apparent low bidder. Did the IFBs from those GAO decisions explicitly state “Attendance to the site visit is required and no offer will be considered for award without attending the scheduled site visit”? If they did, and GAO still sided with the government, that makes for a stronger government case for awarding to the low bidder. If those IFBs did not contain such a definitive statement, the GAO decisions may be less supportive of awarding to the non-compliant bidder. Also consider that GAO decisions are not binding, nor do they create legal precedent. Only court decisions do that. Awarding to the second lowest bidder could invite a protest from the low bidder for this reason.

After considering the thoughts above along with advice from legal counsel, the contracting officer needs to use his/her business judgment when making the award determination.