MYF Controller questioned a local procedure involving taxiing an aircraft back on an active parallel runway during simultaneous runway operations.

Narrative

A Cessna was executing takeoff and landing to a full stop on Runway 28L (north pattern). Simultaneously; another Cessna was executing touch and go's on Runway 28R (north pattern). There were also other aircraft inbound to MYF and on frequency. It was daytime. (Reference 7110.65 3-8-4 simultaneous opposite direction operation and the minima; table 3-8-2). Montgomery Airfield does not meet the allowable conditions due to our parallel runway centerline proximity. MYF parallel centerlines are separated by 500 FT. Scenario: The Local Controller on position solicited to the pilot of one Cessna to back-taxi onto Runway 28L. The Cessna was executing opposite direction taxi operation on the active Runway 28L while Cessna was on very short final executing a touch and go unto Runway 28R. I did inform the Local Controller of the opposite direction operation regulations and strongly advised not to solicit this to the pilot. The question I pose is does this classify as an aircraft taxiing on an active runway as an operation regardless of the direction? If so; then without doubt we are violating the orders. With the level of newness and inexperience currently at our facility; I feel that we should not participate in this activity. 1) Controllers that I have seen thus far do not incorporate placards when and if a back-taxi operation is being done. 2) I feel we are inviting an unnecessary accident to occur because very frequently at our busy VFR Tower we catch training pilots attempt landings on the wrong runway assigned. Therefore; I recommend refraining from opposite direction back-taxi operations on either parallel runway; unless of course; we are down to using one runway as the active runway in use.