arXiv:2610.19859v1 Announce Type: new Abstract: Existing placement studies for pinching-antenna systems (PASS) usually assume that antenna movement is instantaneous and free. In practice, actuators move at finite speeds and must pause radiation while repositioning. This makes performance depend on consecutive antenna positions, turning placement into an edge-weighted longest-path problem on a temporal trellis. We also show that an obstacle blocks a wider range of antenna positions as it approaches the user, causing sudden performance drops that make multi-step lookahead essential, and that once obstacle height is included every blockage event shadows at least a fixed minimum length of waveguide. We give an exact offline solution with complexity O(TMS) and bound the per-slot loss of a W-step receding-horizon policy by O(1/W). Measurements show that the required lookahead window is set by shadow width rather than by waveguide length. Across 20 random seeds, the exact policy delivers 17.7% higher max-min throughput than per-slot optimization under blockage, and matches it when no blockers are present.