If your players get a hot tip or some other private info that they have no desire to pursue will they call up their fixer and tip him off. Stuff like a seeing a couple of gangers boosting a car in another gangs territory. Or knowing that some starlet is making out with a married CEO cause you saw them sneak into a closet.

If so what do they expect back?

tips back or

Having a fixer is necessary. Having a fixer that likes you is priceless. (but not in a mastercard sort of way, 'cause that joke is way too overdone)

That kind of behavior is part of what is encompassed by a level 2 contact vs a level 1 contact. Hence the potential tn mods or extra work a level 2 can provide. Players doing that in return to a level 2 contact are staying very true to the roleplay part of it, as a GM if they did it consistently Id give them a break on the contact upkeep costs (free biz for the fixer brings in enough nuyen). If they did it to a level 1 Id give them the chance to make that into a level 2. Depending on how in depth they go in this back and forth, and to what level they take it, it could lead to a level 3 over a campaign.