Individual raid pass should be changed to a univeral raid card with credits instead
Similar to how all the arcades use these cards to track how much money you have rather than carry tokens, raid passes should just have a raid credit amount on it instead...
THEN, raid costs should be adjusted accordingly so Tier 1 = 25 credits, Tier 2 = 50 credits, Tier 3 = 75 credits and Tier 4 raids = 100 credits...
No one wants to waste their pass on a Tier 1 or 2 raid already and having it cost less may make people willing to try to get a Magickarp or some of the starters, etc...
Awards can be adjusted accordingly if needed...This will also help rurals, smaller groups try to get more TMs if they can do a raid 1 or 2 battle more often since tier 3/4 battles are out of luck for most solo players...
Answers
I suppose they didn't do it this way so people would have to BUY passes if they visited the city and do city raids with more people...
Save 700 raid coins during the week, raid for free on the weekend 7 times...
1 way to prevent this would be to have premium raid credits that can be saved and regular that you can only have 200 credits in...When you use credits, it's taken from the regular credits first...
Problem solved for Niantic and regular players...I'd do karp raids if the cost was cheaper...