[Now if we were established first and *then* made contact, particularly with a lower-tech race.....wait, what am I saying? Look at our own history. We'd give them smallpox blankets or addict them to opium.
The question is if they would be effected by either at all, and how fast they would find a cure for either if they are affected.
The argument was intended to show prior agency, not a specific mechanism. Suffice it to say, if we found something of ours that made them sick or some chemical compound that they could be addicted to, I don't trust us not to use it to gain an imperialist advantage.
using missiles to deliver geosensor buoys from distance (to quickly and safely scout new systems)
That's actually a really cool idea
Perhaps unfeasible at low tech levels, but still!
I know, right? If only I could mount grav sensors on a buoy, I'd do the same to all the system survey points. The beauty of it is that once it's a feasible option, you could outfit one big-ass survey cruiser, pop into an unsurveyed system, fire off a volley of buoys, then jump out and head for the next system. The buoys would be designed to handle about 300-500 survey points' worth over time, and since you can determine survey points needed for a body before surveying it, you'd know when to fire off 2 or 3 for those really large planets. Probably wouldn't be as handy for the A-class stars and larger, just because of the huge orbital distances. But for M- and K-class systems (which you have in spades with a Real Stars start), it'd be handy. Parallel processing of multiple systems at the same time, over a few months.
If there's Precursors hanging around, you only lose a cheap buoy. And if you affix a tiny active sensor to each, you can hopefully pick up ships and populations just before the probe's destruction. The actual buoys are relatively tiny and cheap (and can be manufactured low-tech). It's the delivery system (missile *and* launcher) that are a pain. To be really useful, you'd need a distance of some 500-750 million km. More if you want to use them easily in G-class systems or larger.
If I read Steve's notes on the missile/engine rework correctly, this may actually become a LOT more feasible in the next version. Building a 500 million km range missile will be easy at low-tech...if you don't mind the "speed" being something like 500 km/s or so. You could build up a slew of sensor buoys on very slow, long-range boosters, and just seed these all over unexplored systems, and gets your automated survey results over the course of years or even decades, without any substantial risk to your ships.