It is one great way I've seen games take care of spammers. Make it so they cant afford to spam 10,000 times a day. Eve online was always funny when you could set your own fee. The scammers never wanted to contact me lol.
Only issue is unless you add in a whitelist if you set the fee to high legit uses now can't afforded to carry out the action required. I'm sure some whales would just love to set it to a $500 for there time.
It would be nice if the issue just solved itself by people being education enough to not send the spammers money so they can keep operating. Make it not worth there time in cost due to losses or just not much income where they could be putting resources necessary to run it other places.
I'm sure they will just move to comment spam but at least then they can be swept up and nuked like the bugs they are in a microwave.
I'd like them to be able to set it at $500 too. I doubt there'd be many willing to pay that. Keep in mind it wouldn't stop the transactions from showing.
You could still send a whale 5 SBD (for a steem monsters card for example), it's just the memo field would be greyed out.
You could perhaps make an exception for people you're following.
"If I follow the sender, no minimum. If I don't, set the minimum at .1 SBD"
I'd love them to get a nice little red message "transactions rejected by receiver their minimum threshold of 500$ not met ;p
Sounds good to me.
Although, accounts sending to Bid-bots might not agree. Perhaps these services could cover the cost ;)