Wouldn't an unconditional basic income lead to an inflation that negates its effect? There are several version and denomination for a basic income. In this question, I will call unconditional basic income the situation were all citizens of a country receive regularly a lump-sum of money, independently of their age, their employment status and job,etc. I will assume that, at the moment the basic income is  instituted, it is larger than the poverty threshold. I am also assuming that the basic income is not a substitute of other welfare subsidies.

The concept is gaining popularity these days, and for many reasons, economical or philosophical.

My understanding of offer and demand is that, if people can pay more for a product and are willing to do so, then prices will increase. So, it seems that, after the introduction of the basic income, there will be mechanically a large inflation.  In a short time, people with no job and that relied mostly on the welfare system will be poor again. Worse, people with low income will be closer to the new poverty threshold.

My questions:
1) What natural mechanical effects prevent an over-inflation after the introduction of a substantial basic income? By natural, I mean any direct or indirect effects of the sole introduction of the basic income.

2) If an inflation cannot naturally be avoided, what measures are usually suggested together with the introduction of the basic income?

Edit: my question is close but not an exact duplicate of this question. In the example of the other question, $A$ would receive $30$ and $B$ would receive $90$ for an unconditional basic income of $30$. If the two questions are equivalent, please explain.
Theoretically basic income might have a tendency to increase inflation. But that largely depends on how much is the basic income provided. Usually, the idea of basic income itself means that it is 'basic' and is just sufficient for a subsistence. With such an income level, the problem of inflation does not crop up really. 
However, basic income might have other serious problems with crowding out due to large government spending and the disincentive to work and hence loss of productivity. 

Even if we suppose, there is a large basic money disbursement which can cause inflation, then I think it should not be unconditional. Usually, such plans are in the form of guaranteed employment programs, buying of ration from designated stores and many more measures. However, I still feel these measures are not for tackling inflation rather the disincentive to work.