Bid Tabulations are available upon request. An Informal Solicitation is a procurement accomplished without an invitation for bids, request for proposal, or request for expressions of interest.1.1. Baltimore County is soliciting bids from firms specializing in conducting Background. Investigations and Polygraph Examinations. In a Competitive Sealed Proposal, a Request for Proposals ("RFP") is issued, Vendors submit a Technical Proposal and a Cost.