Hello Mikis and welcome to the forum.
I thought your original question was a good time to draw attention to our well traveled author and esteemed TDA member, Thomas McGee. His rules from his publication, R.O.P.E. (Rules Of Poker and Etiquette) are more detailed than most other rule-sets. This is one suggestion Thomas mentioned that I agree with and would support:
CONFLICTING RULES AND IRREGULARITIES
The 50% Rule
Too often players reaching for chips attempting to call, accidentally are made to raise because of the 50% Rule. It states that if a player throws in 50% or more of an amount needed to raise, then they will be forced to complete the raise. Tournament participants not being professional players frequently mistakenly grab 1 to many chips needed to make the call.
Example: Blinds are $100-$200, there is significant action and Player A is 5th to enter the pot and accidentally has 3 chips stick together and puts out $300 in the pot. They instantly try to retrieve the ill added chip. But it is too late under current rules and they are required to raise and thus have reopened the betting. Rules should not force players to raise and make them put at risk more chips than they originally intended to invest and worse reopen the betting to players that have already acted.
I believe the rule should be changed to 51% or more. Many blinds levels contain 1-2 chip blinds where if a 3rd chip equal to the predominant denomination being used for the blind is accidentally added, when trying to call, would result in a forced raise situation. Being forced to raise only creates tension between the player and the dealer and does not lessen any undesirable action that it is supposed diminish.
These levels all use 1-2 chip blinds:
25-50
100-200
500-1,000
1,000-2,000
5,000-10,000
10,000-20,000
25,000-50,000
50,000-100,000
As you can see the possibility of making a forced raise progressively gets higher as the chip values and blind levels increase. No player ever wants to be placed in the awkward position of being forced to raise simply because they accidentally grabbed three chips and put them in the pot intending to call but instead being forced to raise. Not everyone is an expert chip handler and chips can just as easily stick together.