cast complimentary passport

[newyork1114]

I am a bit confused, My brother in law works for ESPN an affiliate of Disney. He and other employees receive from time to time "Complimentary Passports". his name is on the back, of course he is always working and hasn't been able to use them. I am going to Tampa on March 07 so he gave me 4 passes to use. On the back 2 passports say "In Florida present this ticket at any main entrance turnstile for a 1 day park hopper pass"... 2 say "in Florida exchange this ticket at Guest Relations Window for a 1 day park hopper pass"...
I will have my Grandchildren with me 10, 12, 14 years of age. he swears anyone he gives them to can use them but I don't want to get up to the gate with 3 kids to be told I can not use them or that my brother in law whose name is printed on the back needs to be with us. I don't want the kids let down like that.
Does any one have any information at all about these?
I tried to call the ticketing office and have gotten no positive answers.
Also, the letter and guidelines that came with the passports is confusing. It says main entrance admission passes will allow 4 guests in on one pass. Are the passports that state take to the Main entrance what they are talking about?
Any and all help will be greatly appreciated.
I leave in 10 days..yikes..