Is it true that i have to play my guitar unlocked for a while just after i restring in order to season the top part of the strings, i.e. at the headstock, or else when i lock, it will just go out of tune?
No, it's not true.
or is it a problem with my locking system because i tune it before locking and after locking it seems to be much sharper, and some people told me not to touch the tuners at the saddle as it will affect the intonation.
No, there's nothing wrong with you locking system.
No, touching the fine-tuners at the saddles will not affect your intonation.
Your tuning will definitely be sharper when you lock it down. It's just like when fret a note with lots of pressure, it'll sound different as compared to when you fret a note with less pressure.
Solution? Tune it slightly flatter, (as per Mr.Whitestrat's advice), this is to compensate for the locking down, which will make your tunings slightly sharper.
And whoever it is that told you that the saddles tuners would affect your intonation, doesn't really know his stuff.
The purpose of those saddle fine-tuners is to fine-tune your tuning after you've locked it down. As it's tag implies.
Going right back the start, you mentioned 'seasoning'. Now that's a valid point. What people usually like to do is to stretch the strings, so that the tunings will be stable.
Just grab a string and move it up and down, careful not to snap the strings. Repeat for all the strings.
One drawback with string-stretching is that there are complains that the strings sound less crisp and lively. Up to you to decide though, really.
Hope that I've been of some help.
