First time, and it happened twice

[representing]

Tonight, Girls JV. First time ever this has happened.

After warning horn goes off for a Time-Out, visiting team sends a player to the table to sub in. I noticed this happened when I was getting ready to hand the ball in for a throw-in. I turn around to tell the coach that after the first horn goes off (warning horn) the table is closed for any substitutions.

With 10 seconds left in the close game, a Time-Out is granted and right after the first horn goes off I see a player going to the table to check in from the same team as above. I tell her that she has to wait so the coach pulls her and puts her back on the bench as she probably wasn't going to get in at all.

Rulebook still in the car, too lazy to get it but did I get this right? It was one of those moments where something hardly happens, but when it does the rule pops out of your sub-conscious mind. I believe I did look this up after seeing it happen in an NCAA game where the official stopped the player from coming in after the warning horn goes off.