NO.
I have previously avoided entering this discussion, however I consider the fact that you are changing your terms WITHOUT approval of existing customers to be abuse of their keys.
You do NOT own your customers keys and you do NOT have permission to implement this simply because you 'notify' them.
Change this immediately to an OPT IN service or I will begin flagging your payment posts with 100% downvote weight and begin to solicit other whales to do the same.
Also, if you look here https://steemit.com/steemvoter/@steemvoter/steemvoter-com-s-new-home
this seems to be the very first "payout" post, and its a month old and has over 500 votes.
The point... that around half of the "payout" post voters signed up to SV as a free service and then got converted to the one payout vote per day because they didnt opt out.
If you look at @anotherjoe 's comment on that thread, you will see that he, at least, didn't know this was happening.
One other point to this -- they kind of do, though obviously they shouldnt.
Now granted, im not huge crypto guy, but the way ive always understood it is having the key is the same as owning the key. Thats precisely why doing it this way is (vice how streemian and SC do it) is unadvisable.
EDIT -- Based on subsequent discussion, the above is probably not correct.
There isn't a large difference in practice between the two methods. In either case to revoke access you need to change the authorization data attached to your account. In the case of steemvoter you have to change your key. In the case of steemian you have to remove steemian from the authorization list. It is much the same thing.
You could argue that giving your key to steemvoter increases the risk of key disclosure but at the same time authorizing steemian to act on your account means you are exposed to steemian's key being disclosed.
There is, however, a major difference in usability and user-friendliness since web users have no way to add or remove steemian from their authority list, but they do have the ability change their keys. If I were implementing a service like, for usability purposes given the current state of the steem/it tools I'd probably use the steemvoter method.
hm... thinking about it, i suppose that makes sense because you hold the higher keys, and could reverse any changes. edited to reflect
its not necessarily an overwhelming concern with something like SV (though it would be with money changing hands and the active key), but one other potential difference i see is that you can (i think) see who did what with authorizations
@marcgodard here. This is why I choose this method. I saw it as less intrusive. I also make sure that deleted accounts removes the keys and are never used again.
QFT
for the record, I am not 100% sure that the daily payout post itself was opt-in, rather than opt out.
check this comment on the original SV thread.
https://steemit.com/steemit/@marcgodard/steemit-s-free-voting-bot-for-everyone#@sigmajin/re-marcgodard-steemit-s-free-voting-bot-for-everyone-20160921t011837023z
and marcgoodards reply.
At the time it was initially advertised, it was advertised as a for-free service. The people who signed up between then and the daily vote posts were, apparently, given the same opt-out option SV now proposes for his "guild".
Though i suppose one could argue that it's at least somewhat different in that, even though the service was advertised as free, there was always the "fine print" in the tos .