The only way people would pay fees is if miners started declining free or near-zero-fee txs for processing, (or fees were enforced by the protocol or something). But if that happened, you don't get to spam for near-zero cost or zero cost.
Gee, what a good idea. Amazing how its never been thought of before in Bitcoin.....
2016-01-30 21:35:33 ERROR: AcceptToMemoryPool: free transaction rejected by rate limiter
2016-01-30 21:35:42 receive version message: /bitnodes.21.co:0.1/: version 70002, blocks=395848, us=109.78.0.155:8333, peer=109
2016-01-30 21:35:51 ERROR: AcceptToMemoryPool: free transaction rejected by rate limiter
2016-01-30 21:35:54 ERROR: AcceptToMemoryPool: free transaction rejected by rate limiter
2016-01-30 21:36:04 ERROR: AcceptToMemoryPool: free transaction rejected by rate limiter
2016-01-30 21:36:05 ERROR: AcceptToMemoryPool: free transaction rejected by rate limiter
2016-01-30 21:36:07 ERROR: AcceptToMemoryPool: free transaction rejected by rate limiter
2016-01-30 21:36:21 ERROR: AcceptToMemoryPool: free transaction rejected by rate limiter
2016-01-30 21:36:25 ERROR: AcceptToMemoryPool: nonstandard transaction: dust
2016-01-30 21:36:37 ERROR: AcceptToMemoryPool: free transaction rejected by rate limiter
2016-01-30 21:36:38 ERROR: AcceptToMemoryPool: free transaction rejected by rate limiter
2016-01-30 21:36:38 ERROR: AcceptToMemoryPool: free transaction rejected by rate limiter
2016-01-30 21:36:38 ERROR: AcceptToMemoryPool: free transaction rejected by rate limiter
2016-01-30 21:36:49 ERROR: AcceptToMemoryPool: free transaction rejected by rate limiter
2016-01-30 21:36:50 ERROR: AcceptToMemoryPool: free transaction rejected by rate limiter
2016-01-30 21:36:55 ERROR: AcceptToMemoryPool: free transaction rejected by rate limiter
2016-01-30 21:36:55 ERROR: AcceptToMemoryPool: free transaction rejected by rate limiter
2016-01-30 21:37:00 ERROR: AcceptToMemoryPool: free transaction rejected by rate limiter
2016-01-30 21:37:10 ERROR: AcceptToMemoryPool: free transaction rejected by rate limiter
2016-01-30 21:37:13 ERROR: AcceptToMemoryPool: free transaction rejected by rate limiter
2016-01-30 21:37:13 ERROR: AcceptToMemoryPool: free transaction rejected by rate limiter
2016-01-30 21:37:26 ERROR: AcceptToMemoryPool: free transaction rejected by rate limiter
2016-01-30 21:37:29 ERROR: AcceptToMemoryPool: free transaction rejected by rate limiter
2016-01-30 21:37:35 ERROR: AcceptToMemoryPool: free transaction rejected by rate limiter
2016-01-30 21:37:49 ERROR: AcceptToMemoryPool: free transaction rejected by rate limiter
2016-01-30 21:37:54 ERROR: AcceptToMemoryPool: free transaction rejected by rate limiter
2016-01-30 21:37:59 ERROR: AcceptToMemoryPool: free transaction rejected by rate limiter
2016-01-30 21:38:00 ERROR: AcceptToMemoryPool: free transaction rejected by rate limiter
2016-01-30 21:38:05 ERROR: AcceptToMemoryPool: free transaction rejected by rate limiter
2016-01-30 21:38:19 receive version message: /Satoshi:0.8.6/: version 70002, blocks=275686, us=109.78.0.155:8333, peer=110
2016-01-30 21:38:19 Added time data, samples 55, offset +0 (+0 minutes)
2016-01-30 21:38:19 nTimeOffset = +0 (+0 minutes)
2016-01-30 21:38:20 ERROR: AcceptToMemoryPool: free transaction rejected by rate limiter
2016-01-30 21:38:20 ERROR: AcceptToMemoryPool: free transaction rejected by rate limiter
2016-01-30 21:38:20 ERROR: AcceptToMemoryPool: free transaction rejected by rate limiter
2016-01-30 21:38:21 ERROR: AcceptToMemoryPool: free transaction rejected by rate limiter
2016-01-30 21:38:25 ERROR: AcceptToMemoryPool: free transaction rejected by rate limiter
2016-01-30 21:38:26 ERROR: AcceptToMemoryPool: free transaction rejected by rate limiter