There is a mandate in the law that a copy of the notice issued to the garnishee should be forwarded to the assessee. S. 226(3). The High Court has to step in  4 ITR-OL 452 (Ker) to lift a garnishee order in the absence of such service of notice.
Drawing reference to the recovery guidelines laid down by the Division Bench in 345ITR 71 (page 79) the High Court ( Single Bench ) held inclined to find that the provision definitely mandates that notice
shall be forwarded to the assessee and though a hearing is not contemplated, the specific provision cannot be treated as a dead-letter. It is intended, at least, to alert the assessee so as to bring to the notice of the Recovery Officer any anomalies in making such demand and also to avail of the statutory remedies available to the assessee and for arranging its affairs to deal with the contingency of the bank accounts being frozen and debited off the amounts ; against the demand.
At the same time the court restrained itself to go into the conduct of the individual officer, who is supposedly new to office and had only acted in anxiety to protect revenue and further therefore held that” this court cannot also discount the pressure brought upon subordinate officers; when, as referred to in UTI Mutual Fund (supra), the Chairman, Central Board of Direct Taxes, himself, has addressed the Chief Commissioner; Director Generals, etc., of the Income-tax Department, requiring speedy recovery and consequent weightage in the normal incidence of service. This court has to necessarily practise the judicial restrain, it preached at the beginning. Suffice it to observe that the zeal to serve the nation shall not cross the bounds of law and result in over-zealous actions infringing upon the rights of citizens, for whom the State exists.”
Yet further in another instance a division bench in  424 ITR 283 (Ker) called the attachment and recovery effected in haste after it found that the recovery was effected on the same day when the notice was issued to the garnishee.