A couple observations. First, when and how do you expect the feedback? I'll take the Fire Alarm contractor as the one who I am the perpetrator on. I am usually going to ask the person who does the maintenance for a bid. I am not going to initiate contact to anyone after the bid unless I am awarded the contract and I need to vet a low enough bid. If I am contacted after bid but prior to award, I may tell a person they were not low, or they were low, but I won't ever reveal numbers until I am sure they can't use that information to undercut someone else. The same should go for a GC. If a GC reveals my number to another electrician, they can use that information to solicit a different GC to use them. Lastly, if a customer says they don't want me to ever share their number, I won't share their number, but I also won't reveal other numbers to them.