Ah, right, you are correct about that. However, you can't make that assumption as there are various mods out there that depend on bots mounted to players, for example the dueling weapons. I also have heard of a new mod in progress to handle armor/suits (aka Suitmod) that will also make use of bots to save on image slot space, which would further increase the chances of this issue arising.
To be exact, the following situations are my understanding how bot visibility in first person works:
1) If only one bot is mounted to the player, that bot is invisible.
2) If two or more bots are mounted to the player, the first bot mounted will stay invisible while the rest will be visible
- Caveat: If the first bot is mounted to the driver seat/slot 0 as defined in the datablock, that will become visible rather than the second bot mounted. The rest will still show up as normal iirc.
3) Anything mounted to bots mounted to you is always visible.
Note that depending on the bounding box of the bot datablock, the visibility of it can pop in/out. The stable, reliable bot-based mods I've seen utilize dead bots with large bounding boxes as a result, ex vectorScale("20 20 20", 4).