Air carrier Line Check Airman reported ORD ATC has an unsafe procedure where it does not give flight crew a clearance to the ramp nor a specific route to follow; and expects pilots to traverse to the ramp using see and avoid principles.

Narrative

I was performing a CA observation from the jumpseat on this flight. After landing in ORD and clearing the runway (28C); the FO/Line Check Airman (LCA) called company operations on radio #2 to confirm our gate assignment and availability in accordance with company procedures for that airport. After crossing Runway 28R; ATC/Ground instructed us to; Taxi LL; hold short of B. What's your gate?" The FO/LCA replied with Gate XX. ATC then asked us if they were going to take us into the ramp. If I remember correctly; the FO replied in the affirmative (but that may have been an assumption). ATC then instructed us; "Left turn on B." As we came abeam our respective ramp; having no further instructions from ATC; we assumed the controller needed us to continue taxiing until traffic conditions permitted an entry to the ramp. Once we passed Taxiway A6; the Ground Controller asked; "Were they not ready for you?" Perplexed; the FO replied that they were ready. The Ground Controller; also confused; then directed us to taxi "A5 here and then go back on A to the ramp." This was the first time ATC actually cleared us "to the ramp." Now; while this clearance took us geographically to the ramp; there was no instruction to "contact" the Ramp. After receiving no further instructions (and not wanting to pass our ramp a second time); we switched frequencies and contacted the Ramp as we approached on A.The following day; I called ORD Tower to discuss our confusion and inquire what their expectation was for inbound aircraft. After speaking with two different controllers; I learned that their expectation is for pilots to contact the Ramp Controller as they are abeam the ramp on B and taxi across A (a taxiway in the movement area). I asked ATC if the ramp controllers have ownership of Taxiway A (i.e.; a letter of agreement) or if they have situational awareness of aircraft taxiing on A and was told by one controller; "I don't know;" and by another controller; "follow the rules of the road" (in other words "see and avoid"). One controller told me I still need to monitor the Ground frequency because until I am actually on the ramp; I am still on the movement area (true; especially when I have not been told to switch frequencies!).My concern is that pilots arriving at ORD are expected (without an actual ATC clearance or instruction) to cross an active taxiway using "see and avoid" principles at a busy Class B airport; and this is supposed to be done based on an unspoken/unwritten expectation for crews that may or may not be familiar with that airport. Personally; I don't have an issue doing that. In fact; I would prefer to taxi all over the airport surface using "see and avoid" and not having to ask permission and follow lengthy and complicated taxi clearances. The problem is; legally; I can't do that. From a safety perspective; there is a reason for having a distinction between a movement and non-movement area and one should not be treated like the other. I understand why ATC prefers this arrangement (traffic/frequency congestion); but it puts pilots in a confusing and potentially dangerous situation. In effect; ATC in Chicago is asking pilots to violate the FAR 14 CFR 91.129; paragraph (i); which requires pilots to obtain a clearance before operating an aircraft on a taxiway at a controlled airport; and the Aeronautical Information Manual (AIM) Section 4-3-18; which requires approval prior to operating an aircraft on a movement area when the Tower is in operation.Cause: Ground controllers at Chicago are not following the FAA JO 7110.65; Section 3-7-2 (by not giving a "specific route to follow" with their taxi clearance); and Section 2-1-17 (by not advising pilots who to contact and when). It should be noted that this first section is also not followed completely by ground controllers at DFW; although the second section is followed there. Airports where ATC follows both sections well include ATL; CLT; DCA; and PHL.Suggestion: Ground controllers at Chicago should give specific taxi instructions and state (not assume) where pilots should contact Ramp on arrival; especially if the pilot is not actually at the ramp yet. For example; in this scenario: "Aircraft Y; taxi LL B contact Ramp approaching;" or even better; "Taxi LL B A10; and contact Ramp." There appears to be room for a regional or even narrow-body aircraft to hold on those intersecting taxiways and not block A or B. If there isn't; aircraft should be taxied as we were - onto A eastbound and then contact the Ramp from there. It's not right to ask pilots to traverse sections of the movement area without an explicit clearance; especially without verbal or written guidance for crews that may be unfamiliar with that airport."