You just acknowledged that there are transactions with >83 bytes in the blockchain added before v30. But then you immediately contradict yourself by saying, “and now in addition large OP_RETURNs are possible”. Clearly, they were already possible, if there were already “around 15” added before v30 (I think there is a lot more, and my query is still running). So how do you reconcile this contradiction in your mind, while still believing that the change to the default settings in the v30 client makes a difference? I can help you out: it doesn’t. Changing the default settings in a client does not affect consensus rules. All valid transactions can and will be added to the blockchain. Client settings are not consensus rules. What is your preference, spam in a prunable field, like OP_RETURN, or spam in permanent ones, such as UTXOs? As BitMex research showed by storing images in private keys, everything in Bitcoin is data, so it will always be vulnerable to abuse.

BitMEX Blog

Bitcoin OP_RETURN & Image Storage: Spam Debate

Abstract: We look again at the OP_Return policy limit issue and the related topic of storing images in the blockchain. The argument is not going a...

So far, I have found 13,574 OP_RETURN outputs > 83 bytes, before v30 was released. ~25,300 blocks left to be checked.

My scan of the blockchain data for OP_RETURN outputs > 83bytes, prior to block 930600, when the default size setting was updated to 100000 bytes, is complete. I started at block 290,000, since thats about where the OP_RETURN field was introduced. ``` ========= RESULTS ========= Scan range: blocks 290,000 to 930,599 Time elapsed: 27.56 hours Average speed: 6.5 blocks/second Blocks scanned: 640,600 Transactions scanned: 1,258,073,612 Transactions with OP_RETURN > 83 bytes: 577 Total OP_RETURN outputs > 83 bytes: 13,962 Size distribution by frequency (top 20): 142 bytes: 4,833 outputs 140 bytes: 2,931 outputs 138 bytes: 1,950 outputs 111 bytes: 420 outputs 137 bytes: 378 outputs 143 bytes: 247 outputs 122 bytes: 246 outputs 129 bytes: 237 outputs 139 bytes: 223 outputs 121 bytes: 198 outputs 118 bytes: 164 outputs 120 bytes: 140 outputs 131 bytes: 121 outputs 135 bytes: 76 outputs 141 bytes: 69 outputs 128 bytes: 65 outputs 132 bytes: 64 outputs 133 bytes: 62 outputs 153 bytes: 53 outputs 145 bytes: 46 outputs ... and 474 more distinct sizes Size range: 84 - 984593 bytes ``` It is notable that the vast majority of outputs are using less than 150 bytes, so probably used by various scripts, rather than jpeg data. This means that almost all of the spam is in non-prunable, permanent records, probably inscriptions.