I think it might not be legal to bait in deer to shoot them, but you'd need to check that up with someone who actually knows.
It seems to me that the reaction of deer to feeding varies by area - as you've seen above it works in some places however I have very wary sika and not only do they not eat it but it scares them away. I've seen calves take a mouthful (I experimented with lots of stuff but usually wheat/barley/grain but have tried carrots and other things as well) before departing but my observation was (trail cameras) that once they'd seen it, maybe even taken a sniff, adult deer simply avoided the area and I never saw them again. To my eye it looked like it scared them off. The cameras revealed that it was eventually the crows that ate it, because it was in forestry it took them quite a while to find it so the deer often had weeks to get used to it before the crows got there. What it did attract was pine martens - mice came to feed on the grain and pine martens came to eat the mice.
This video shows the reaction of a wee sika stag to peanuts that were put out for the pine martens, the reaction to grain was basically the same but this is the only video I have online of very similar circumstances to putting down grain for them. Bigger stags don't come this close and run immediately, hinds will come for a close look, the occasional calf might take a mouthful
