I've been trying to figure out what I'd do for admin buttons on my panel and thought I'd post what I ended up with.
I definitely wanted an obvious and dedicated Pause button, and Exit function so guests could figure it out and change games on their own (I'm using Mamewah for my front end).
Upon reading this thread, and a few others, and asking another few questions of my own, I determined that there are other admin functions I might like to have accessible from the control panel but that nobody else would need them, so I don't see putting dedicated buttons in for this.
I also wanted to avoid the P1Start+P2Start = Exit problem. Which also made me think, I don't think I want a simple single dedicated Exit button where somebody could hit it accidentally and exit a game when they didn't really want to. I decided I did want Exit to have to be a combination of two different buttons so you'd have to deliberately press both to Exit.
I also do have enough extra inputs on my I-Pac/4 that I could add some admin buttons without having to use a Shift function. (Though I ended up using a Shift function anyway as you'll see below.)
So here's what I ended up with.
I have 2 admin buttons on the top of my panel, the same number I'd have if I had a single dedicated Pause and Exit button. BUT, both buttons by themselves are Pause. The left Pause button is also my shift button. Then the shifted function of the right Pause button is to Exit (Esc). So Exit is press and hold the left Pause button, then press the right Pause button. (And the buttons are on opposite sides of the panel so somebody can't accidentally press both buttons at the same time with one hand.) These 2 buttons are wired to P1B7 and P1B8 on my I-Pac/4 since I'm only using 6 buttons for P1 & P2. So I used WinIPac to redefine P1B7 as the Shift key.
So, while I was at it, I figured nobody would accidentally hold down the pause button like they might a P1Start button, so I added more admin functions using the Shift function.
Shifted P1B1, P1B2, and P1B3 correspond to F1, F2, and F3 respectively. Then I have the P1 shifted joystick directions mapped the same as they come in the I-Pac by default.
While the argument could certainly be made that I don't need those additional shifted admin functions, I definitely don't think it can hurt to have them based on me using the Pause button as the Shift key and not having to have any additional physical buttons to support them.
Oh, and I took the other advice of changing Mamewah to use something other than ESC to exit it so typical players won't be able to exit the front end. I did program a shift function though to exit Mamewah so I could still do it without a keyboard if I wanted to.