Police searches inside stadiums

Not against the law. You can subject a visitor to private or public property to a search. If you look around the entrance, there is probably a sign stating that visitors may be subject to search. We used to get pat downs going into WB after 9/11.

if you had a service dog it would have been shot

That's what I thought. I didn't make a big deal about it. He zeroed in on my cellphone first. I guess a galaxy s3 can look like a flask? Idk.

you should have screamed rape

Terry v. Ohio

Depends on who you ask. There currently is a federal inquiry and a case being brought to the Supreme Court regarding this. The main argument is that homeland security illegally violates the 4th amendment when randomly pulling people out of the line to search. It will apply to types of facilities. Currently for a stadium or place like this when a ticket is purchased you basically consent to the search. Most facilities have that policy and it is implied when you buy the ticket that you agree. Another out there I saw was specific to public universities. the Supreme Court ruled publically funded schools do not require a search warrant but must have reasonable grounds to search.

25 year old white guy at a baseball game. I think I look ordinary.

I had a cellphone bulge that may have looked like a flask maybe. That's all I can think.

They are consent searches which require no suspicion of criminal activity to conduct the search. Probably when you purchase a ticket and/or at the entrance of the facility you get notice that you are subject to being searched upon entering the facility. You do have the option of not entering and therefore not being subjected to the search. LINK