A recent GAO decision should serve to caution offerors to be careful what they include with their proposals. Any information that contradicts the proposal or otherwise does not conform to the terms of the solicitation could result in disqualification.
In Independent Systems, Inc., B-413246 (Comp. Gen. Sept. 15, 2016), GAO held that the agency could reasonably disqualify an offeror based on extraneous information the offeror included with the intent of providing the agency with more information, but not changing the terms of the offer.