I dunno, IMO the reason it's being exploited is more because it doesn't adequately penalize aggressive/unsafe/unfair driving - right now all it does is give a penalty to both cars that came into contact regardless of how or why it happened. Sometimes this can lead to a double penalty for people that get rammed and then go off track.
This what I think needs to happen:
1). There needs to be penalty severities, perhaps on a scale of 1-5 or 1-10. Right now it's an equal amount of penalty for slightly overshooting a corner as it is to slam into a car at full speed. A slight overshoot or use of outfield should result in a minor penalty, and infield track cuts, heavy/high speed contact with walls, barriers, and other cars should be more heavily penalized.
2). Tracks need better-defined "penalty zones". Going from the penalty scale, there needs to be parts of the track that can be set to different penalty strengths - here's shouldn't be equal penalty for going wide at the end of a former and making a heavy cut to the infield. Basically if a car goes a tad wide and use the outfield at the end of a corner it should be a level 1 track boundary infraction, if the car takes the corner too hard and goes deep into the the outfield or cuts a little bit into the infield it should be a level 2 or 3 track boundary infraction, and if someone takes a heavy shortcut or hits an outer wall at high speed it should be a level 4 or 5 track boundary infraction.
3). There needs to be a system that can analyze car behavior when contact occurs. Given the trackable data already available in-game, it shouldn't be hard to set up a system that can examine from (or even slightly before) a point of contact, and then see if the contact results in a car going off track. If so, the penalty otherwise given for off-track driving could be waived, and the driver responsible could receive a more severe penalty as I outlined in the first bit. To avoid exploits, it could be made void if the off-track driving is on the infield - otherwise people could use the system to bounce off of cars on the outside of a corner, cut in, and then have their penalty waived while taking a shortcut, and giving all the heavy penalties to the car they rammed.
In order for this to work PD may have to set acceptable speeds, car orientations, and steering angles (as underlying software rules ["if, thens"], not as driving regulations) relative to the track per-class. I don't think breaching them should result in penalty unless contact is involved, it could get really hairy otherwise. What may need to happen is having this system analyzing over a set amount of time or a set amount track length after a point of contact - perhaps if on a corner, analyze for the length of the corner and an additional 50-100 meters, and if on a straight, analyze for 3-4 seconds after the point of contact.
Additionally, I do think all cars involved in the contact situation should still receive a penalty - I think keeping that in will encourage people to do their best to avoid touching other cars just as it does now - but the heavier penalties need to land on the offenders.
4). There needs to be additional ways to earn SR points. I can't think of many ways you could that would be reasonable, but given points 2 and 3, it would seem logical if those systems are in place then it wouldn't be too hard to have a system that awards points for avoiding accidents. Basically when the contact system outlined in #3 comes on, the software could label the cars involved as "at risk" during the analyzing process, and slowing down,giving additional space to those cars, or avoiding wrecks should result in an SR gain. It would make sense to have more pints for more cars avoided. This "at risk" label system could also apply to cars that are losing grip or spinning, or are stopped or near-stopped on the track. Additionally if the "at risk" cars are covering too much of the road and/or your speed is too high to slow down or make a safe pass (and the system can accurately calculate all this data), then the boundary penalties outlined in #2 should at minimum be made void. Perhaps make a balancing act based on how many points are awarded for avoiding the accident vs. how severe the boundary violation is.
There could also be points awarded for letting faster vehicles pass when class racing comes around. The only other ideas I had were getting off the racing line when recovering from an accident or waiting for a safe track re-entry (just to give a little bit of an opportunity to mend a screw-up) and perhaps for backing off to avoid going two+ wide on thin high-speed corners on tracks like Tokyo and some parts of the Nurburgring.
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Basically the system right now is just "-point if contact", "-point if off track/wall contact", and "+point if no contact or off track in sector", and it's just not adequate, especially with the esport goals PD have.