It is totally free for your users to check for CLAMS and we provide different options for them to dig if they chose not to go the client route (we also provide a link to the Github for the client).
You always seem to forget to mention the fees. It's totally free to check for CLAMs, but if they want to get paid in BTC you pay 0.005 BTC for 4.6 CLAMs, worth 4.6 * 0.006 = 0.0276 BTC at current prices. That's an 81% fee:
>>> 100 - 0.005 * 100 / 0.0276
81.884
That seems like something that might be worth pointing out.