I wanna share my opinion about stickers, their positive and negative effects. 

   One of the difficulties playing violin is an intonation. There is possible to make a mistake for 1/3-1/8 of tone and it will be noticable. Nothing on a fingerboard will show you where is a note supposed to be. This creates difficulties for begginers who cannot forecast the sound in each particular 1-2mm of the fingerboard. That`s why "stickers issue" arises.

   First point to consider is musical experience. Those begginers who used to play other instruments will probably have in mind the idea about how each note is supposed to sound. Therefore, I suggest, that there is no need of stickers. It will become okay in a short time.

  Beginners who have just started playing violin are perhaps confused by the sound. It is almost impossible to find the right note on violin, if you even don`t know how should it sound. The fingerboard seems scary for them and they have no ideas how to be okay with that. I was in this situation. Moreover, when I bought my violin I "played" nearly 5 hours on instrument which is not tuned appropriate. Then I recognized that probably something is wrong with that This type of begginers should consider use of stickers.

  What the benefits of the stickers? I tend to think that when you just started playing violin stickers will be very helpful. It is, of course, doesn`t make your intonation ideal, but it helps in recognizing the sound of each note. Once again, it is impossible to play right note when you have no ideas how it should sound. So, before trying to find the right note you should have in your mind the sound of the note. That`s why I suggest that the stickers are helpful. You also training the appropriate disposition of your fingers.

  Negative effect? Since you started to use stickers you became "addicted" to them. You always look at stickers because you afraid of wrong intonation. And you will probably see no reasons to put them off. Someting like: "I am still not confident enough, I will use them one more month". The reality is that you will never confident in your ability to find the right note when you use stickers!!! Your playing will be no more than such a mechanical work (look at sticker, put your finger. again). I can suggest that violin was created to make a beautiful music but not to mechanically change position of your fingers and bowing simultaneously.   

  A few days ago, playing a month, I put off the stickers. Everything changed since that time! Now I even do not need to look at my fingerboard playing music that I learned (except some difficult parts). I can close my eyes and hear music! It is amazing!

 So, the idea is that stickers are okay and helpful at first steps. Since you`ve learned the sound of each note (in 1st position) the stickers will only make your playing limited.