It was Europcar, but in the past also have found similar with Avis and Budget as well. With Europcar, the top of the search results screen shows the discount voucher code and has wording similar to lowest rate applied. I noticed when the voucher code was removed the same daily costs appeared irrespective of the voucher being used. I suspect that consumers have been used to using group coupons and some retailers/suppliers have cottoned onto it using it as a marketing/impulse buying tool irrespective if a actual discount has resulted from the use of the codes. The goup coupon sites also provide low cost/free redirection traffic to the retailer, and has been an effective marketing tool in the past and has potential to be rorted as a result.
The other thnig we have noticed is the advertised vouchers appear to offer unilateral discounts but when looking at the details, the alleged discounts only apply to a limited number of locations/countries.
Sifting through them takes time to check what is actually being offered, if anything of value.
@TillySouth, the other thing we noticed from booking our upcoming holiday is that travel insurance can cover rental car excess up to $5000. When booking rental cars, there is often a recommended option to reduce the standard rental car excess from thousand(s) $$$ to a hundred(s) $$$ for what seems a small sum... say $15-30 per day. This might be okay for a one to two day hire, but for longer term hire the cost to reduce the excess through a car rental company can amount to more than the cost of a comprehensive travel insurance which can also covers the high excess. If one is risk adverse or wants to ensure that are not hit with a huge excess in the case of a rental car crash, one shouId be wary or buying excess reduction through the rental car company. It is far more cost effective to buy travel insurance instead...)and may not cost more if one already takes out travel ihsurance when traveling overseas like we always do). One just needs to read the travel insurance policy cover to ensure that such is covered..
The other shonky practice is electricity and gas retailers offering 10, 15, 25% discounts only to find the discount applies to the energy usage charges and not metering, billing or network charges. In reality for most consumers a 10% discount on energy charges equates to a maximum 3-5 percent discount on the total bill. Our experience for gas is we use about $12 of gas per quarter on a $111 bill...we receive a 6% discount on gas usage which equates to about a $0.65 saving on $110, about 0.5% real saving. Such is also deceptive conduct duping consumers.