Well, as I allude to with the Budget score, category scores can be damaged over the course of the bidding race. If a Troubleshooter steals budget or R&D, those scores go down by 1 point and the opposing corporation gains a point.

That said, I am not a fan of forcing posters to go down railroad tracks because of dice rolls. The way I envision it, a high security score limits the actions a hostile Troubleshooter can take by default, and also determines whether you can even detect enemy troubleshooters at all.

Having a higher security score than the rival corporation has a troubleshooting score means that your security trips up the Troubleshooter, and your forces are made aware of their presence and intrusion. This doesn't mean the Troubleshooting effort is an automatic failure - the poster controlling the troubleshooter still has the option of trying to have them continue their mission, and the posters can reach an agreement dependent upon the context of the situation. Inversely, if the security score is lower than the opposing Troubleshooting score, the Troubleshooter gets in and out undetected - and in this case, all the Security score does is limit or else mitigate the damage the Troubleshooter can do. Security can even still capture/kill the Troubleshooter if they attempt something that this 'passive' security prevents.

Security Score of 4 versus a Troubleshooting score of 7? The Troubleshooter plants a nail bomb in your manufacturing center.

If that Security Score is 5 instead, the Troubleshooter wasn't able to gain access to your manufacturing center and instead 'merely' assassinates your chief engineer.

If this gets enough interest, I'll include a brief 'rule of thumb' description of how differences between Security/Troubleshooting will affect Troubleshooting attempts. Something important to keep in mind though that a lot of this will be dependent upon contextual information provided by each poster.