[Scripting Question] Random event on entering map

Hello Everyone,

Still on my project to create a game for teaching I had the idea of implementing a limited number of pokemon of the same species in the computer, this relatively to the respect of biodiversity.
I don't want to make it so it's impossible to capture if you already have one. I think it would be more realistic and fun if an environmental guy shows up randomly and checks the computer of the player then gives him a fine if he/she has two or more pokemon of the same species.

So my questions are:
1)How to create a global event that will autocheck its conditions every second (I think that's how the time of day works) or everytime the player enters a new map
2)How to check if the computer + the party contains more than one vulpix for example.

For the random I guess I can figure it out using variables.

Thank you in advance guys/girls!

Hello,

So i tryed this code :

Events.onMapChange+=proc {|sender,e|
Envi=rand(4)
if Envi==1
pbWait(20)
Kernel.pbMessage(_INTL("Hey there"))
end
}
Which kinda works but the message is visible only if it triggers when I start the game and not when I change map. (I added the pbWait because i thought this way the character would walk on the map then see the message but each time he's waiting on the previous map and I have the sound of a message displaying but nothing is written and when I press action I then arrive on the next map.

How could I change this? I tried pbDisplay, but for some reason I had a nil class error

Edit: It works but I had to use a trick because I didn't understand the first problem, here is what I found:
Events.onMapChange+=proc {|sender,e|
$game_variables[1]=rand(4)
}
Events.onStepTaken+=proc {
if $game_variables[1]==1
Kernel.pbMessage(_INTL("Hey there"))
$game_variables[1]=0
end
}
If someone knows how to make it more simple I would love to hear how :)
Now How do I Display a scene (pictures) and make a check weither the character has twice the same species?

Thank you very much for your time