Hi
Yes you absolutely must purchase RR active chips , in fact you cant purchase the system without first signing a contract saying that you will only use RR chips. I use them for Cyclocross and may have 7 races in a day but none would be more than 50 per race so yes I have some logistics to handle so that my day goes well, Registration for some races does not open until a previous race has been completed and the chips have been collected after that race and reassigned for the later race while interim races are going on in between, works really well as it is a series and the same riders and clubs are always the same so they know the story and work well to implement it. I am only a tiny outfit and cant afford for a single chip to go missing so strict collection of chips is a must (these work out to be approx 60 euro each (close to 100 if you factor in the cost of replacement incl postage of a single 1) , and I lost one this season so not happy. I have 99 now.
when you get home store them in a cold shed without electricity and in a tin or aluminium box to keep them asleep. 125Khz (which is absolutely everywhere) will trigger them to wake and spring to action, you dont want that !!
Battery wise they are supposed to last 5 years, I had one fail after a few months but it was absolutely quibble free replacement, their service is great to be fair.
If you want to be able to absolutely walk away from your post for 10 minutes during a race and come back knowing that everything will have been captured and it is guaranteed , then active is great but be prepared to shell out big bucks every 5 years, It wasnt an easy decision for me but Im glad I made it.
With CX you may see a rider 6 to 7 times per race, If one passing is missed the race results are screwed, I just didnt want the chance with that using passive plus the chance of close finishes are common too.
All the best
JK