Well, in World War I it did. Aldo Fraccaroli, in "Italian Warships of World War I", Ian Allan , 1970, lists eight such vessels:
FOLGORE, ex Italian merchant ship, ex Austro-Hungarian SS ZETA, 104 grt/1914, in service 1.1.1917 (after conversion at Arsenale di Venezia), sunk Nov. 1917 in the Piave river by gunfire, raised Nov.-Dec.1917 and recommissioned. Discarded 31.7.1919, returned to previous owners.
GALLINARA, ex merchant motor schooner NOSTRA SIGNORA DEL BOSCHETTO, ex French AMIRAL FORET, built by J. Guerruel at Antibes as a sailing ship, 106 grt/1908, in service 1.7.1915 (purchased from owner A. Mortola of Genova, which had had her engined). Sunk 22-23/11/1915 by A-H destroyer LIKA off Brindisi.
GIANICOLO, ex river steamer of Soc. Ital. di Navigaz. Marittima e Fluviale, Roma, 262 or 266grt/1907, built by N. Odero at Sestri Ponente, comm. 16.5.1915 as a decoy ship/minelayer. Discarded 21.1.1920 and sold commercially to "Il Mare" SA, Genova, 1926 to Andrea Zanchi, Genova. Iscritto nel LR fino al 1931.
MALAMOCCO, a motor schooner of 300 grt, ex .....,comm. 1916, unarmed, operated in Autumn 1917 as a decoy ship together with the sub PACINOTTI. Discarded 1920.
PANTELLERIA, ex merchant motor schooner (brigantino-goletta) CUORE DI GESU', 199 or 204 grt, comm. 1.7.1915, former owner Raffaele Di Maio. Sunk 14.8.1916 South of Taranto by a torpedo from U4 after a gun battle (the Q-ship had 2 x 47 mm) or 1.12.1916 6 mi. SE of Giannutri by U 32.
SAETTA, ex Italian merchant ship, ex A-H SS LOWCEN, 104 grt/1915, seized at Venice 5.1915 while building by Savinem, comm. 1.1.1917 (after conversion at the Arsenale di Venezia). Sunk in Venice lagoon 17.12.1917 (where she was used as a gunboat after the Caporetto retreat) by artillery fire; raised, repaired and again in service. Discarded 31.7.1919, again mercantile LOWCEN for the Comp. di Antivari of Giuseppe Volpi fu Ernesto, Venice, service on the Bojana under Austrian or Montenegrin flag (?), then laid up Venice; in 1926 purchased by the Regia Marina as the harbour tug SAN PIETRO (stricken in 1971).
SASSARI, a passenger/cargo steamer, 1489 grt, ex LADY ROBERTS, built 1897 by Ailsa, Troon, for the British & Irish Steam Packet Co. Ltd., purchased 8.1913 by Soc. di Nav. Marittima Italiana as SASSARI, 1915 Serv. di Navigaz. di Stato, comm. Regia Marina as an AMC (8.1916) but used until 12.1916 as a decoy ship, then rejected as too slow (11 kts) and used as a convoy escort ship. Returned to owner 11.4.1919. 5.1923 to Italia Soc. di Nav., same month to CITRA, Comp. Ital. TRAnsatlantica, 1.1932 to Florio Soc. di Nav., 2.1932 to Tirrenia Flotte Riunite (Florio e CITRA). Broken up at Naples in 1933. In mid-August 1916 she had a fight in the Tyrrhenian Sea with U 35.
USTICA, ex merchant motor schooner RAFFAELE PADRE, 198 later 239 grt, built 4.1915 by Guglielmo Donnarumma at Castellammare di Stabia for Gennaro & Ciro Capano, Torre del Greco. Comm. Regia Marina 1.7.1915, used at first as a decoy ship then as a searchlight-ship in Valona harbour. Disc. 11.9.1919 and returned to owners as RAFFAELE PADRE (later R. Capano & Figli, Torre del Greco, then in the 1930s Luigi & Ignazio Ciccolella, Trieste). Stricken from Lloyd's Register in 1934.
As far as I know, no Q-ship in WW 2.
Modificata da de domenico, 02 febbraio 2011 - 11:00 .