How would you have those if the player wasn't high risk?
Thats also not what you said earlier about the situation.
If you have legitimately started the SOF process for a high risk player, the information provided along with deposit levels, gameplay etc give cause for you to suspect the funds aren't legitimate, and the customer refuses to supply clarification (assuming your requests are reasonable) then yes, a SAR should be submitted.
What casinos shouldn't be doing is blanket requesting every customer, then submitting a SAR when a customer refuses.
Didn't say casinos submit SAR for every player but that they do them, think i said few per month or something which is really small part of these requests. It's of course always up to casino and other are different than other but if you release funds to player without getting satisfying replies to your request, you are paying funds when you are suspicious about origin of deposits.
edit: There's not much sense but UKGC for example have added that line to their guide lines about levels of SAR submissions and they do expect operators to submit them. What request by operators are reasonable decided by operator (and take responsibilities about wrong doing, not asking enough or breaching some other regulations by asking too much). I don't have any agenda to tell SOW:s are good or reasonable, fact just unfortunately are that these will be requested probably more in future than less. There are loads of different guidances which probably also confuse some operators as you only usually learn that you haven't done enough when regulator find it in audit but not usually what has been too much. Seem that many operators have chosen better be safe than sorry, it do cost resources and players satisfaction so don't think many would do them just for fun but instead willing to be safe as possible.